This file is indexed.

/usr/lib/python3/dist-packages/pymongo/collection.py is in python3-pymongo 3.4.0-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
# Copyright 2009-2015 MongoDB, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Collection level utilities for Mongo."""

import collections
import datetime
import warnings

from bson.code import Code
from bson.objectid import ObjectId
from bson.py3compat import (_unicode,
                            integer_types,
                            string_type)
from bson.raw_bson import RawBSONDocument
from bson.codec_options import CodecOptions
from bson.son import SON
from pymongo import (common,
                     helpers,
                     message)
from pymongo.bulk import BulkOperationBuilder, _Bulk
from pymongo.command_cursor import CommandCursor
from pymongo.collation import validate_collation_or_none
from pymongo.cursor import Cursor
from pymongo.errors import ConfigurationError, InvalidName, OperationFailure
from pymongo.helpers import _check_write_command_response
from pymongo.helpers import _UNICODE_REPLACE_CODEC_OPTIONS
from pymongo.operations import _WriteOp, IndexModel
from pymongo.read_concern import DEFAULT_READ_CONCERN
from pymongo.read_preferences import ReadPreference
from pymongo.results import (BulkWriteResult,
                             DeleteResult,
                             InsertOneResult,
                             InsertManyResult,
                             UpdateResult)
from pymongo.write_concern import WriteConcern

try:
    from collections import OrderedDict
    _ORDERED_TYPES = (SON, OrderedDict)
except ImportError:
    _ORDERED_TYPES = (SON,)

_NO_OBJ_ERROR = "No matching object found"
_UJOIN = u"%s.%s"


class ReturnDocument(object):
    """An enum used with
    :meth:`~pymongo.collection.Collection.find_one_and_replace` and
    :meth:`~pymongo.collection.Collection.find_one_and_update`.
    """
    BEFORE = False
    """Return the original document before it was updated/replaced, or
    ``None`` if no document matches the query.
    """
    AFTER = True
    """Return the updated/replaced or inserted document."""


class Collection(common.BaseObject):
    """A Mongo collection.
    """

    def __init__(self, database, name, create=False, codec_options=None,
                 read_preference=None, write_concern=None, read_concern=None,
                 **kwargs):
        """Get / create a Mongo collection.

        Raises :class:`TypeError` if `name` is not an instance of
        :class:`basestring` (:class:`str` in python 3). Raises
        :class:`~pymongo.errors.InvalidName` if `name` is not a valid
        collection name. Any additional keyword arguments will be used
        as options passed to the create command. See
        :meth:`~pymongo.database.Database.create_collection` for valid
        options.

        If `create` is ``True``, `collation` is specified, or any additional
        keyword arguments are present, a ``create`` command will be
        sent. Otherwise, a ``create`` command will not be sent and the
        collection will be created implicitly on first use.

        :Parameters:
          - `database`: the database to get a collection from
          - `name`: the name of the collection to get
          - `create` (optional): if ``True``, force collection
            creation even without options being set
          - `codec_options` (optional): An instance of
            :class:`~bson.codec_options.CodecOptions`. If ``None`` (the
            default) database.codec_options is used.
          - `read_preference` (optional): The read preference to use. If
            ``None`` (the default) database.read_preference is used.
          - `write_concern` (optional): An instance of
            :class:`~pymongo.write_concern.WriteConcern`. If ``None`` (the
            default) database.write_concern is used.
          - `read_concern` (optional): An instance of
            :class:`~pymongo.read_concern.ReadConcern`. If ``None`` (the
            default) database.read_concern is used.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. If a collation is provided,
            it will be passed to the create collection command. This option is
            only supported on MongoDB 3.4 and above.
          - `**kwargs` (optional): additional keyword arguments will
            be passed as options for the create collection command

        .. versionchanged:: 3.4
           Support the `collation` option.

        .. versionchanged:: 3.2
           Added the read_concern option.

        .. versionchanged:: 3.0
           Added the codec_options, read_preference, and write_concern options.
           Removed the uuid_subtype attribute.
           :class:`~pymongo.collection.Collection` no longer returns an
           instance of :class:`~pymongo.collection.Collection` for attribute
           names with leading underscores. You must use dict-style lookups
           instead::

               collection['__my_collection__']

           Not:

               collection.__my_collection__

        .. versionchanged:: 2.2
           Removed deprecated argument: options

        .. versionadded:: 2.1
           uuid_subtype attribute

        .. mongodoc:: collections
        """
        super(Collection, self).__init__(
            codec_options or database.codec_options,
            read_preference or database.read_preference,
            write_concern or database.write_concern,
            read_concern or database.read_concern)

        if not isinstance(name, string_type):
            raise TypeError("name must be an instance "
                            "of %s" % (string_type.__name__,))

        if not name or ".." in name:
            raise InvalidName("collection names cannot be empty")
        if "$" in name and not (name.startswith("oplog.$main") or
                                name.startswith("$cmd")):
            raise InvalidName("collection names must not "
                              "contain '$': %r" % name)
        if name[0] == "." or name[-1] == ".":
            raise InvalidName("collection names must not start "
                              "or end with '.': %r" % name)
        if "\x00" in name:
            raise InvalidName("collection names must not contain the "
                              "null character")
        collation = validate_collation_or_none(kwargs.pop('collation', None))

        self.__database = database
        self.__name = _unicode(name)
        self.__full_name = _UJOIN % (self.__database.name, self.__name)
        if create or kwargs or collation:
            self.__create(kwargs, collation)

        self.__write_response_codec_options = self.codec_options._replace(
            unicode_decode_error_handler='replace',
            document_class=dict)

    def _socket_for_reads(self):
        return self.__database.client._socket_for_reads(self.read_preference)

    def _socket_for_primary_reads(self):
        return self.__database.client._socket_for_reads(ReadPreference.PRIMARY)

    def _socket_for_writes(self):
        return self.__database.client._socket_for_writes()

    def _command(self, sock_info, command, slave_ok=False,
                 read_preference=None,
                 codec_options=None, check=True, allowable_errors=None,
                 read_concern=DEFAULT_READ_CONCERN,
                 write_concern=None,
                 parse_write_concern_error=False,
                 collation=None):
        """Internal command helper.

        :Parameters:
          - `sock_info` - A SocketInfo instance.
          - `command` - The command itself, as a SON instance.
          - `slave_ok`: whether to set the SlaveOkay wire protocol bit.
          - `codec_options` (optional) - An instance of
            :class:`~bson.codec_options.CodecOptions`.
          - `check`: raise OperationFailure if there are errors
          - `allowable_errors`: errors to ignore if `check` is True
          - `read_concern` (optional) - An instance of
            :class:`~pymongo.read_concern.ReadConcern`.
          - `write_concern`: An instance of
            :class:`~pymongo.write_concern.WriteConcern`. This option is only
            valid for MongoDB 3.4 and above.
          - `parse_write_concern_error` (optional): Whether to parse a
            ``writeConcernError`` field in the command response.
          - `collation` (optional) - An instance of
            :class:`~pymongo.collation.Collation`.

        :Returns:

            # todo: don't return address

          (result document, address of server the command was run on)
        """
        return sock_info.command(
            self.__database.name,
            command,
            slave_ok,
            read_preference or self.read_preference,
            codec_options or self.codec_options,
            check,
            allowable_errors,
            read_concern=read_concern,
            write_concern=write_concern,
            parse_write_concern_error=parse_write_concern_error,
            collation=collation)

    def __create(self, options, collation):
        """Sends a create command with the given options.
        """
        cmd = SON([("create", self.__name)])
        if options:
            if "size" in options:
                options["size"] = float(options["size"])
            cmd.update(options)
        with self._socket_for_writes() as sock_info:
            self._command(
                sock_info, cmd, read_preference=ReadPreference.PRIMARY,
                write_concern=self.write_concern,
                parse_write_concern_error=True,
                collation=collation)

    def __getattr__(self, name):
        """Get a sub-collection of this collection by name.

        Raises InvalidName if an invalid collection name is used.

        :Parameters:
          - `name`: the name of the collection to get
        """
        if name.startswith('_'):
            full_name = _UJOIN % (self.__name, name)
            raise AttributeError(
                "Collection has no attribute %r. To access the %s"
                " collection, use database['%s']." % (
                    name, full_name, full_name))
        return self.__getitem__(name)

    def __getitem__(self, name):
        return Collection(self.__database, _UJOIN % (self.__name, name))

    def __repr__(self):
        return "Collection(%r, %r)" % (self.__database, self.__name)

    def __eq__(self, other):
        if isinstance(other, Collection):
            return (self.__database == other.database and
                    self.__name == other.name)
        return NotImplemented

    def __ne__(self, other):
        return not self == other

    @property
    def full_name(self):
        """The full name of this :class:`Collection`.

        The full name is of the form `database_name.collection_name`.
        """
        return self.__full_name

    @property
    def name(self):
        """The name of this :class:`Collection`."""
        return self.__name

    @property
    def database(self):
        """The :class:`~pymongo.database.Database` that this
        :class:`Collection` is a part of.
        """
        return self.__database

    def with_options(
            self, codec_options=None, read_preference=None,
            write_concern=None, read_concern=None):
        """Get a clone of this collection changing the specified settings.

          >>> coll1.read_preference
          Primary()
          >>> from pymongo import ReadPreference
          >>> coll2 = coll1.with_options(read_preference=ReadPreference.SECONDARY)
          >>> coll1.read_preference
          Primary()
          >>> coll2.read_preference
          Secondary(tag_sets=None)

        :Parameters:
          - `codec_options` (optional): An instance of
            :class:`~bson.codec_options.CodecOptions`. If ``None`` (the
            default) the :attr:`codec_options` of this :class:`Collection`
            is used.
          - `read_preference` (optional): The read preference to use. If
            ``None`` (the default) the :attr:`read_preference` of this
            :class:`Collection` is used. See :mod:`~pymongo.read_preferences`
            for options.
          - `write_concern` (optional): An instance of
            :class:`~pymongo.write_concern.WriteConcern`. If ``None`` (the
            default) the :attr:`write_concern` of this :class:`Collection`
            is used.
          - `read_concern` (optional): An instance of
            :class:`~pymongo.read_concern.ReadConcern`. If ``None`` (the
            default) the :attr:`read_concern` of this :class:`Collection`
            is used.
        """
        return Collection(self.__database,
                          self.__name,
                          False,
                          codec_options or self.codec_options,
                          read_preference or self.read_preference,
                          write_concern or self.write_concern,
                          read_concern or self.read_concern)

    def initialize_unordered_bulk_op(self, bypass_document_validation=False):
        """Initialize an unordered batch of write operations.

        Operations will be performed on the server in arbitrary order,
        possibly in parallel. All operations will be attempted.

        :Parameters:
          - `bypass_document_validation`: (optional) If ``True``, allows the
            write to opt-out of document level validation. Default is
            ``False``.

        Returns a :class:`~pymongo.bulk.BulkOperationBuilder` instance.

        See :ref:`unordered_bulk` for examples.

        .. note:: `bypass_document_validation` requires server version
          **>= 3.2**

        .. versionchanged:: 3.2
          Added bypass_document_validation support

        .. versionadded:: 2.7
        """
        return BulkOperationBuilder(self, False, bypass_document_validation)

    def initialize_ordered_bulk_op(self, bypass_document_validation=False):
        """Initialize an ordered batch of write operations.

        Operations will be performed on the server serially, in the
        order provided. If an error occurs all remaining operations
        are aborted.

        :Parameters:
          - `bypass_document_validation`: (optional) If ``True``, allows the
            write to opt-out of document level validation. Default is
            ``False``.

        Returns a :class:`~pymongo.bulk.BulkOperationBuilder` instance.

        See :ref:`ordered_bulk` for examples.

        .. note:: `bypass_document_validation` requires server version
          **>= 3.2**

        .. versionchanged:: 3.2
          Added bypass_document_validation support

        .. versionadded:: 2.7
        """
        return BulkOperationBuilder(self, True, bypass_document_validation)

    def bulk_write(self, requests, ordered=True,
                   bypass_document_validation=False):
        """Send a batch of write operations to the server.

        Requests are passed as a list of write operation instances (
        :class:`~pymongo.operations.InsertOne`,
        :class:`~pymongo.operations.UpdateOne`,
        :class:`~pymongo.operations.UpdateMany`,
        :class:`~pymongo.operations.ReplaceOne`,
        :class:`~pymongo.operations.DeleteOne`, or
        :class:`~pymongo.operations.DeleteMany`).

          >>> for doc in db.test.find({}):
          ...     print(doc)
          ...
          {u'x': 1, u'_id': ObjectId('54f62e60fba5226811f634ef')}
          {u'x': 1, u'_id': ObjectId('54f62e60fba5226811f634f0')}
          >>> # DeleteMany, UpdateOne, and UpdateMany are also available.
          ...
          >>> from pymongo import InsertOne, DeleteOne, ReplaceOne
          >>> requests = [InsertOne({'y': 1}), DeleteOne({'x': 1}),
          ...             ReplaceOne({'w': 1}, {'z': 1}, upsert=True)]
          >>> result = db.test.bulk_write(requests)
          >>> result.inserted_count
          1
          >>> result.deleted_count
          1
          >>> result.modified_count
          0
          >>> result.upserted_ids
          {2: ObjectId('54f62ee28891e756a6e1abd5')}
          >>> for doc in db.test.find({}):
          ...     print(doc)
          ...
          {u'x': 1, u'_id': ObjectId('54f62e60fba5226811f634f0')}
          {u'y': 1, u'_id': ObjectId('54f62ee2fba5226811f634f1')}
          {u'z': 1, u'_id': ObjectId('54f62ee28891e756a6e1abd5')}

        :Parameters:
          - `requests`: A list of write operations (see examples above).
          - `ordered` (optional): If ``True`` (the default) requests will be
            performed on the server serially, in the order provided. If an error
            occurs all remaining operations are aborted. If ``False`` requests
            will be performed on the server in arbitrary order, possibly in
            parallel, and all operations will be attempted.
          - `bypass_document_validation`: (optional) If ``True``, allows the
            write to opt-out of document level validation. Default is
            ``False``.

        :Returns:
          An instance of :class:`~pymongo.results.BulkWriteResult`.

        .. seealso:: :ref:`writes-and-ids`

        .. note:: `bypass_document_validation` requires server version
          **>= 3.2**

        .. versionchanged:: 3.2
          Added bypass_document_validation support

        .. versionadded:: 3.0
        """
        if not isinstance(requests, list):
            raise TypeError("requests must be a list")

        blk = _Bulk(self, ordered, bypass_document_validation)
        for request in requests:
            if not isinstance(request, _WriteOp):
                raise TypeError("%r is not a valid request" % (request,))
            request._add_to_bulk(blk)

        bulk_api_result = blk.execute(self.write_concern.document)
        if bulk_api_result is not None:
            return BulkWriteResult(bulk_api_result, True)
        return BulkWriteResult({}, False)

    def _legacy_write(self, sock_info, name, cmd, acknowledged, op_id,
                      bypass_doc_val, func, *args):
        """Internal legacy write helper."""
        # Cannot have both unacknowledged write and bypass document validation.
        if (bypass_doc_val and not acknowledged and
                    sock_info.max_wire_version >= 4):
            raise OperationFailure("Cannot set bypass_document_validation with"
                                   " unacknowledged write concern")
        listeners = self.database.client._event_listeners
        publish = listeners.enabled_for_commands

        if publish:
            start = datetime.datetime.now()
        rqst_id, msg, max_size = func(*args)
        if publish:
            duration = datetime.datetime.now() - start
            listeners.publish_command_start(
                cmd, self.__database.name, rqst_id, sock_info.address, op_id)
            start = datetime.datetime.now()
        try:
            result = sock_info.legacy_write(
                rqst_id, msg, max_size, acknowledged)
        except Exception as exc:
            if publish:
                dur = (datetime.datetime.now() - start) + duration
                if isinstance(exc, OperationFailure):
                    details = exc.details
                    # Succeed if GLE was successful and this is a write error.
                    if details.get("ok") and "n" in details:
                        reply = message._convert_write_result(
                            name, cmd, details)
                        listeners.publish_command_success(
                            dur, reply, name, rqst_id, sock_info.address, op_id)
                        raise
                else:
                    details = message._convert_exception(exc)
                listeners.publish_command_failure(
                    dur, details, name, rqst_id, sock_info.address, op_id)
            raise
        if publish:
            if result is not None:
                reply = message._convert_write_result(name, cmd, result)
            else:
                # Comply with APM spec.
                reply = {'ok': 1}
            duration = (datetime.datetime.now() - start) + duration
            listeners.publish_command_success(
                duration, reply, name, rqst_id, sock_info.address, op_id)
        return result

    def _insert_one(
            self, sock_info, doc, ordered,
            check_keys, manipulate, write_concern, op_id, bypass_doc_val):
        """Internal helper for inserting a single document."""
        if manipulate:
            doc = self.__database._apply_incoming_manipulators(doc, self)
            if not isinstance(doc, RawBSONDocument) and '_id' not in doc:
                doc['_id'] = ObjectId()
            doc = self.__database._apply_incoming_copying_manipulators(doc,
                                                                       self)
        concern = (write_concern or self.write_concern).document
        acknowledged = concern.get("w") != 0
        command = SON([('insert', self.name),
                       ('ordered', ordered),
                       ('documents', [doc])])
        if concern:
            command['writeConcern'] = concern

        if sock_info.max_wire_version > 1 and acknowledged:
            if bypass_doc_val and sock_info.max_wire_version >= 4:
                command['bypassDocumentValidation'] = True
            # Insert command.
            result = sock_info.command(
                self.__database.name,
                command,
                codec_options=self.__write_response_codec_options,
                check_keys=check_keys)
            _check_write_command_response([(0, result)])
        else:
            # Legacy OP_INSERT.
            self._legacy_write(
                sock_info, 'insert', command, acknowledged, op_id,
                bypass_doc_val, message.insert, self.__full_name, [doc],
                check_keys, acknowledged, concern, False,
                self.__write_response_codec_options)
        if not isinstance(doc, RawBSONDocument):
            return doc.get('_id')

    def _insert(self, sock_info, docs, ordered=True, check_keys=True,
                manipulate=False, write_concern=None, op_id=None,
                bypass_doc_val=False):
        """Internal insert helper."""
        if isinstance(docs, collections.Mapping):
            return self._insert_one(
                sock_info, docs, ordered,
                check_keys, manipulate, write_concern, op_id, bypass_doc_val)

        ids = []

        if manipulate:
            def gen():
                """Generator that applies SON manipulators to each document
                and adds _id if necessary.
                """
                _db = self.__database
                for doc in docs:
                    # Apply user-configured SON manipulators. This order of
                    # operations is required for backwards compatibility,
                    # see PYTHON-709.
                    doc = _db._apply_incoming_manipulators(doc, self)
                    if not (isinstance(doc, RawBSONDocument) or '_id' in doc):
                        doc['_id'] = ObjectId()

                    doc = _db._apply_incoming_copying_manipulators(doc, self)
                    ids.append(doc['_id'])
                    yield doc
        else:
            def gen():
                """Generator that only tracks existing _ids."""
                for doc in docs:
                    # Don't inflate RawBSONDocument by touching fields.
                    if not isinstance(doc, RawBSONDocument):
                        ids.append(doc.get('_id'))
                    yield doc

        concern = (write_concern or self.write_concern).document
        acknowledged = concern.get("w") != 0

        command = SON([('insert', self.name),
                       ('ordered', ordered)])
        if concern:
            command['writeConcern'] = concern
        if op_id is None:
            op_id = message._randint()
        if bypass_doc_val and sock_info.max_wire_version >= 4:
            command['bypassDocumentValidation'] = True
        bwc = message._BulkWriteContext(
            self.database.name, command, sock_info, op_id,
            self.database.client._event_listeners)
        if sock_info.max_wire_version > 1 and acknowledged:
            # Batched insert command.
            results = message._do_batched_write_command(
                self.database.name + ".$cmd", message._INSERT, command,
                gen(), check_keys, self.__write_response_codec_options, bwc)
            _check_write_command_response(results)
        else:
            # Legacy batched OP_INSERT.
            message._do_batched_insert(self.__full_name, gen(), check_keys,
                                       acknowledged, concern, not ordered,
                                       self.__write_response_codec_options, bwc)
        return ids

    def insert_one(self, document, bypass_document_validation=False):
        """Insert a single document.

          >>> db.test.count({'x': 1})
          0
          >>> result = db.test.insert_one({'x': 1})
          >>> result.inserted_id
          ObjectId('54f112defba522406c9cc208')
          >>> db.test.find_one({'x': 1})
          {u'x': 1, u'_id': ObjectId('54f112defba522406c9cc208')}

        :Parameters:
          - `document`: The document to insert. Must be a mutable mapping
            type. If the document does not have an _id field one will be
            added automatically.
          - `bypass_document_validation`: (optional) If ``True``, allows the
            write to opt-out of document level validation. Default is
            ``False``.

        :Returns:
          - An instance of :class:`~pymongo.results.InsertOneResult`.

        .. seealso:: :ref:`writes-and-ids`

        .. note:: `bypass_document_validation` requires server version
          **>= 3.2**

        .. versionchanged:: 3.2
          Added bypass_document_validation support

        .. versionadded:: 3.0
        """
        common.validate_is_document_type("document", document)
        if not (isinstance(document, RawBSONDocument) or "_id" in document):
            document["_id"] = ObjectId()
        with self._socket_for_writes() as sock_info:
            return InsertOneResult(
                self._insert(sock_info, document,
                             bypass_doc_val=bypass_document_validation),
                self.write_concern.acknowledged)

    def insert_many(self, documents, ordered=True,
                    bypass_document_validation=False):
        """Insert an iterable of documents.

          >>> db.test.count()
          0
          >>> result = db.test.insert_many([{'x': i} for i in range(2)])
          >>> result.inserted_ids
          [ObjectId('54f113fffba522406c9cc20e'), ObjectId('54f113fffba522406c9cc20f')]
          >>> db.test.count()
          2

        :Parameters:
          - `documents`: A iterable of documents to insert.
          - `ordered` (optional): If ``True`` (the default) documents will be
            inserted on the server serially, in the order provided. If an error
            occurs all remaining inserts are aborted. If ``False``, documents
            will be inserted on the server in arbitrary order, possibly in
            parallel, and all document inserts will be attempted.
          - `bypass_document_validation`: (optional) If ``True``, allows the
            write to opt-out of document level validation. Default is
            ``False``.

        :Returns:
          An instance of :class:`~pymongo.results.InsertManyResult`.

        .. seealso:: :ref:`writes-and-ids`

        .. note:: `bypass_document_validation` requires server version
          **>= 3.2**

        .. versionchanged:: 3.2
          Added bypass_document_validation support

        .. versionadded:: 3.0
        """
        if not isinstance(documents, collections.Iterable) or not documents:
            raise TypeError("documents must be a non-empty list")
        inserted_ids = []
        def gen():
            """A generator that validates documents and handles _ids."""
            for document in documents:
                common.validate_is_document_type("document", document)
                if not isinstance(document, RawBSONDocument):
                    if "_id" not in document:
                        document["_id"] = ObjectId()
                    inserted_ids.append(document["_id"])
                yield (message._INSERT, document)

        blk = _Bulk(self, ordered, bypass_document_validation)
        blk.ops = [doc for doc in gen()]
        blk.execute(self.write_concern.document)
        return InsertManyResult(inserted_ids, self.write_concern.acknowledged)

    def _update(self, sock_info, criteria, document, upsert=False,
                check_keys=True, multi=False, manipulate=False,
                write_concern=None, op_id=None, ordered=True,
                bypass_doc_val=False, collation=None):
        """Internal update / replace helper."""
        common.validate_boolean("upsert", upsert)
        if manipulate:
            document = self.__database._fix_incoming(document, self)
        collation = validate_collation_or_none(collation)
        concern = (write_concern or self.write_concern).document
        acknowledged = concern.get("w") != 0
        update_doc = SON([('q', criteria),
                          ('u', document),
                          ('multi', multi),
                          ('upsert', upsert)])
        if collation is not None:
            if sock_info.max_wire_version < 5:
                raise ConfigurationError(
                    'Must be connected to MongoDB 3.4+ to use collations.')
            elif not acknowledged:
                raise ConfigurationError(
                    'Collation is unsupported for unacknowledged writes.')
            else:
                update_doc['collation'] = collation
        command = SON([('update', self.name),
                       ('ordered', ordered),
                       ('updates', [update_doc])])
        if concern:
            command['writeConcern'] = concern
        if sock_info.max_wire_version > 1 and acknowledged:
            # Update command.
            if bypass_doc_val and sock_info.max_wire_version >= 4:
                command['bypassDocumentValidation'] = True

            # The command result has to be published for APM unmodified
            # so we make a shallow copy here before adding updatedExisting.
            result = sock_info.command(
                self.__database.name,
                command,
                codec_options=self.__write_response_codec_options).copy()
            _check_write_command_response([(0, result)])
            # Add the updatedExisting field for compatibility.
            if result.get('n') and 'upserted' not in result:
                result['updatedExisting'] = True
            else:
                result['updatedExisting'] = False
                # MongoDB >= 2.6.0 returns the upsert _id in an array
                # element. Break it out for backward compatibility.
                if 'upserted' in result:
                    result['upserted'] = result['upserted'][0]['_id']

            return result
        else:
            # Legacy OP_UPDATE.
            return self._legacy_write(
                sock_info, 'update', command, acknowledged, op_id,
                bypass_doc_val, message.update, self.__full_name, upsert,
                multi, criteria, document, acknowledged, concern, check_keys,
                self.__write_response_codec_options)

    def replace_one(self, filter, replacement, upsert=False,
                    bypass_document_validation=False, collation=None):
        """Replace a single document matching the filter.

          >>> for doc in db.test.find({}):
          ...     print(doc)
          ...
          {u'x': 1, u'_id': ObjectId('54f4c5befba5220aa4d6dee7')}
          >>> result = db.test.replace_one({'x': 1}, {'y': 1})
          >>> result.matched_count
          1
          >>> result.modified_count
          1
          >>> for doc in db.test.find({}):
          ...     print(doc)
          ...
          {u'y': 1, u'_id': ObjectId('54f4c5befba5220aa4d6dee7')}

        The *upsert* option can be used to insert a new document if a matching
        document does not exist.

          >>> result = db.test.replace_one({'x': 1}, {'x': 1}, True)
          >>> result.matched_count
          0
          >>> result.modified_count
          0
          >>> result.upserted_id
          ObjectId('54f11e5c8891e756a6e1abd4')
          >>> db.test.find_one({'x': 1})
          {u'x': 1, u'_id': ObjectId('54f11e5c8891e756a6e1abd4')}

        :Parameters:
          - `filter`: A query that matches the document to replace.
          - `replacement`: The new document.
          - `upsert` (optional): If ``True``, perform an insert if no documents
            match the filter.
          - `bypass_document_validation`: (optional) If ``True``, allows the
            write to opt-out of document level validation. Default is
            ``False``.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only supported
            on MongoDB 3.4 and above.

        :Returns:
          - An instance of :class:`~pymongo.results.UpdateResult`.

        .. note:: `bypass_document_validation` requires server version
          **>= 3.2**

        .. versionchanged:: 3.4
          Added the `collation` option.

        .. versionchanged:: 3.2
          Added bypass_document_validation support

        .. versionadded:: 3.0
        """
        common.validate_is_mapping("filter", filter)
        common.validate_ok_for_replace(replacement)
        with self._socket_for_writes() as sock_info:
            result = self._update(sock_info, filter, replacement, upsert,
                                  bypass_doc_val=bypass_document_validation,
                                  collation=collation)
        return UpdateResult(result, self.write_concern.acknowledged)

    def update_one(self, filter, update, upsert=False,
                   bypass_document_validation=False,
                   collation=None):
        """Update a single document matching the filter.

          >>> for doc in db.test.find():
          ...     print(doc)
          ...
          {u'x': 1, u'_id': 0}
          {u'x': 1, u'_id': 1}
          {u'x': 1, u'_id': 2}
          >>> result = db.test.update_one({'x': 1}, {'$inc': {'x': 3}})
          >>> result.matched_count
          1
          >>> result.modified_count
          1
          >>> for doc in db.test.find():
          ...     print(doc)
          ...
          {u'x': 4, u'_id': 0}
          {u'x': 1, u'_id': 1}
          {u'x': 1, u'_id': 2}

        :Parameters:
          - `filter`: A query that matches the document to update.
          - `update`: The modifications to apply.
          - `upsert` (optional): If ``True``, perform an insert if no documents
            match the filter.
          - `bypass_document_validation`: (optional) If ``True``, allows the
            write to opt-out of document level validation. Default is
            ``False``.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only supported
            on MongoDB 3.4 and above.

        :Returns:
          - An instance of :class:`~pymongo.results.UpdateResult`.

        .. note:: `bypass_document_validation` requires server version
          **>= 3.2**

        .. versionchanged:: 3.4
          Added the `collation` option.

        .. versionchanged:: 3.2
          Added bypass_document_validation support

        .. versionadded:: 3.0
        """
        common.validate_is_mapping("filter", filter)
        common.validate_ok_for_update(update)
        with self._socket_for_writes() as sock_info:
            result = self._update(sock_info, filter, update, upsert,
                                  check_keys=False,
                                  bypass_doc_val=bypass_document_validation,
                                  collation=collation)
        return UpdateResult(result, self.write_concern.acknowledged)

    def update_many(self, filter, update, upsert=False,
                    bypass_document_validation=False, collation=None):
        """Update one or more documents that match the filter.

          >>> for doc in db.test.find():
          ...     print(doc)
          ...
          {u'x': 1, u'_id': 0}
          {u'x': 1, u'_id': 1}
          {u'x': 1, u'_id': 2}
          >>> result = db.test.update_many({'x': 1}, {'$inc': {'x': 3}})
          >>> result.matched_count
          3
          >>> result.modified_count
          3
          >>> for doc in db.test.find():
          ...     print(doc)
          ...
          {u'x': 4, u'_id': 0}
          {u'x': 4, u'_id': 1}
          {u'x': 4, u'_id': 2}

        :Parameters:
          - `filter`: A query that matches the documents to update.
          - `update`: The modifications to apply.
          - `upsert` (optional): If ``True``, perform an insert if no documents
            match the filter.
          - `bypass_document_validation` (optional): If ``True``, allows the
            write to opt-out of document level validation. Default is
            ``False``.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only supported
            on MongoDB 3.4 and above.

        :Returns:
          - An instance of :class:`~pymongo.results.UpdateResult`.

        .. note:: `bypass_document_validation` requires server version
          **>= 3.2**

        .. versionchanged:: 3.4
          Added the `collation` option.

        .. versionchanged:: 3.2
          Added bypass_document_validation support

        .. versionadded:: 3.0
        """
        common.validate_is_mapping("filter", filter)
        common.validate_ok_for_update(update)
        with self._socket_for_writes() as sock_info:
            result = self._update(sock_info, filter, update, upsert,
                                  check_keys=False, multi=True,
                                  bypass_doc_val=bypass_document_validation,
                                  collation=collation)
        return UpdateResult(result, self.write_concern.acknowledged)

    def drop(self):
        """Alias for :meth:`~pymongo.database.Database.drop_collection`.

        The following two calls are equivalent:

          >>> db.foo.drop()
          >>> db.drop_collection("foo")
        """
        self.__database.drop_collection(self.__name)

    def _delete(
            self, sock_info, criteria, multi,
            write_concern=None, op_id=None, ordered=True,
            collation=None):
        """Internal delete helper."""
        common.validate_is_mapping("filter", criteria)
        concern = (write_concern or self.write_concern).document
        acknowledged = concern.get("w") != 0
        delete_doc = SON([('q', criteria),
                          ('limit', int(not multi))])
        collation = validate_collation_or_none(collation)
        if collation is not None:
            if sock_info.max_wire_version < 5:
                raise ConfigurationError(
                    'Must be connected to MongoDB 3.4+ to use collations.')
            elif not acknowledged:
                raise ConfigurationError(
                    'Collation is unsupported for unacknowledged writes.')
            else:
                delete_doc['collation'] = collation
        command = SON([('delete', self.name),
                       ('ordered', ordered),
                       ('deletes', [delete_doc])])
        if concern:
            command['writeConcern'] = concern

        if sock_info.max_wire_version > 1 and acknowledged:
            # Delete command.
            result = sock_info.command(
                self.__database.name,
                command,
                codec_options=self.__write_response_codec_options)
            _check_write_command_response([(0, result)])
            return result
        else:
            # Legacy OP_DELETE.
            return self._legacy_write(
                sock_info, 'delete', command, acknowledged, op_id,
                False, message.delete, self.__full_name, criteria,
                acknowledged, concern, self.__write_response_codec_options,
                int(not multi))

    def delete_one(self, filter, collation=None):
        """Delete a single document matching the filter.

          >>> db.test.count({'x': 1})
          3
          >>> result = db.test.delete_one({'x': 1})
          >>> result.deleted_count
          1
          >>> db.test.count({'x': 1})
          2

        :Parameters:
          - `filter`: A query that matches the document to delete.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only supported
            on MongoDB 3.4 and above.

        :Returns:
          - An instance of :class:`~pymongo.results.DeleteResult`.

        .. versionchanged:: 3.4
          Added the `collation` option.

        .. versionadded:: 3.0
        """
        with self._socket_for_writes() as sock_info:
            return DeleteResult(self._delete(sock_info, filter, False,
                                             collation=collation),
                                self.write_concern.acknowledged)

    def delete_many(self, filter, collation=None):
        """Delete one or more documents matching the filter.

          >>> db.test.count({'x': 1})
          3
          >>> result = db.test.delete_many({'x': 1})
          >>> result.deleted_count
          3
          >>> db.test.count({'x': 1})
          0

        :Parameters:
          - `filter`: A query that matches the documents to delete.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only supported
            on MongoDB 3.4 and above.

        :Returns:
          - An instance of :class:`~pymongo.results.DeleteResult`.

        .. versionchanged:: 3.4
          Added the `collation` option.

        .. versionadded:: 3.0
        """
        with self._socket_for_writes() as sock_info:
            return DeleteResult(self._delete(sock_info, filter, True,
                                             collation=collation),
                                self.write_concern.acknowledged)

    def find_one(self, filter=None, *args, **kwargs):
        """Get a single document from the database.

        All arguments to :meth:`find` are also valid arguments for
        :meth:`find_one`, although any `limit` argument will be
        ignored. Returns a single document, or ``None`` if no matching
        document is found.

        The :meth:`find_one` method obeys the :attr:`read_preference` of
        this :class:`Collection`.

        :Parameters:

          - `filter` (optional): a dictionary specifying
            the query to be performed OR any other type to be used as
            the value for a query for ``"_id"``.

          - `*args` (optional): any additional positional arguments
            are the same as the arguments to :meth:`find`.

          - `**kwargs` (optional): any additional keyword arguments
            are the same as the arguments to :meth:`find`.

          - `max_time_ms` (optional): a value for max_time_ms may be
            specified as part of `**kwargs`, e.g.

              >>> find_one(max_time_ms=100)
        """
        if (filter is not None and not
                isinstance(filter, collections.Mapping)):
            filter = {"_id": filter}

        max_time_ms = kwargs.pop("max_time_ms", None)
        cursor = self.find(filter,
                           *args, **kwargs).max_time_ms(max_time_ms)

        for result in cursor.limit(-1):
            return result
        return None

    def find(self, *args, **kwargs):
        """Query the database.

        The `filter` argument is a prototype document that all results
        must match. For example:

        >>> db.test.find({"hello": "world"})

        only matches documents that have a key "hello" with value
        "world".  Matches can have other keys *in addition* to
        "hello". The `projection` argument is used to specify a subset
        of fields that should be included in the result documents. By
        limiting results to a certain subset of fields you can cut
        down on network traffic and decoding time.

        Raises :class:`TypeError` if any of the arguments are of
        improper type. Returns an instance of
        :class:`~pymongo.cursor.Cursor` corresponding to this query.

        The :meth:`find` method obeys the :attr:`read_preference` of
        this :class:`Collection`.

        :Parameters:
          - `filter` (optional): a SON object specifying elements which
            must be present for a document to be included in the
            result set
          - `projection` (optional): a list of field names that should be
            returned in the result set or a dict specifying the fields
            to include or exclude. If `projection` is a list "_id" will
            always be returned. Use a dict to exclude fields from
            the result (e.g. projection={'_id': False}).
          - `skip` (optional): the number of documents to omit (from
            the start of the result set) when returning the results
          - `limit` (optional): the maximum number of results to
            return
          - `no_cursor_timeout` (optional): if False (the default), any
            returned cursor is closed by the server after 10 minutes of
            inactivity. If set to True, the returned cursor will never
            time out on the server. Care should be taken to ensure that
            cursors with no_cursor_timeout turned on are properly closed.
          - `cursor_type` (optional): the type of cursor to return. The valid
            options are defined by :class:`~pymongo.cursor.CursorType`:

            - :attr:`~pymongo.cursor.CursorType.NON_TAILABLE` - the result of
              this find call will return a standard cursor over the result set.
            - :attr:`~pymongo.cursor.CursorType.TAILABLE` - the result of this
              find call will be a tailable cursor - tailable cursors are only
              for use with capped collections. They are not closed when the
              last data is retrieved but are kept open and the cursor location
              marks the final document position. If more data is received
              iteration of the cursor will continue from the last document
              received. For details, see the `tailable cursor documentation
              <http://www.mongodb.org/display/DOCS/Tailable+Cursors>`_.
            - :attr:`~pymongo.cursor.CursorType.TAILABLE_AWAIT` - the result
              of this find call will be a tailable cursor with the await flag
              set. The server will wait for a few seconds after returning the
              full result set so that it can capture and return additional data
              added during the query.
            - :attr:`~pymongo.cursor.CursorType.EXHAUST` - the result of this
              find call will be an exhaust cursor. MongoDB will stream batched
              results to the client without waiting for the client to request
              each batch, reducing latency. See notes on compatibility below.

          - `sort` (optional): a list of (key, direction) pairs
            specifying the sort order for this query. See
            :meth:`~pymongo.cursor.Cursor.sort` for details.
          - `allow_partial_results` (optional): if True, mongos will return
            partial results if some shards are down instead of returning an
            error.
          - `oplog_replay` (optional): If True, set the oplogReplay query
            flag.
          - `modifiers` (optional): A dict specifying the MongoDB `query
            modifiers`_ that should be used for this query. For example::

              >>> db.test.find(modifiers={"$maxTimeMS": 500})

          - `batch_size` (optional): Limits the number of documents returned in
            a single batch.
          - `manipulate` (optional): **DEPRECATED** - If True (the default),
            apply any outgoing SON manipulators before returning.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only supported
            on MongoDB 3.4 and above.

        .. note:: There are a number of caveats to using
          :attr:`~pymongo.cursor.CursorType.EXHAUST` as cursor_type:

          - The `limit` option can not be used with an exhaust cursor.

          - Exhaust cursors are not supported by mongos and can not be
            used with a sharded cluster.

          - A :class:`~pymongo.cursor.Cursor` instance created with the
            :attr:`~pymongo.cursor.CursorType.EXHAUST` cursor_type requires an
            exclusive :class:`~socket.socket` connection to MongoDB. If the
            :class:`~pymongo.cursor.Cursor` is discarded without being
            completely iterated the underlying :class:`~socket.socket`
            connection will be closed and discarded without being returned to
            the connection pool.

        .. versionchanged:: 3.4
           Support the `collation` option.

        .. versionchanged:: 3.0
           Changed the parameter names `spec`, `fields`, `timeout`, and
           `partial` to `filter`, `projection`, `no_cursor_timeout`, and
           `allow_partial_results` respectively.
           Added the `cursor_type`, `oplog_replay`, and `modifiers` options.
           Removed the `network_timeout`, `read_preference`, `tag_sets`,
           `secondary_acceptable_latency_ms`, `max_scan`, `snapshot`,
           `tailable`, `await_data`, `exhaust`, `as_class`, and slave_okay
           parameters. Removed `compile_re` option: PyMongo now always
           represents BSON regular expressions as :class:`~bson.regex.Regex`
           objects. Use :meth:`~bson.regex.Regex.try_compile` to attempt to
           convert from a BSON regular expression to a Python regular
           expression object. Soft deprecated the `manipulate` option.

        .. versionchanged:: 2.7
           Added `compile_re` option. If set to False, PyMongo represented BSON
           regular expressions as :class:`~bson.regex.Regex` objects instead of
           attempting to compile BSON regular expressions as Python native
           regular expressions, thus preventing errors for some incompatible
           patterns, see `PYTHON-500`_.

        .. versionadded:: 2.3
           The `tag_sets` and `secondary_acceptable_latency_ms` parameters.

        .. _PYTHON-500: https://jira.mongodb.org/browse/PYTHON-500
        .. _query modifiers:
          http://docs.mongodb.org/manual/reference/operator/query-modifier/

        .. mongodoc:: find
        """
        return Cursor(self, *args, **kwargs)

    def parallel_scan(self, num_cursors, **kwargs):
        """Scan this entire collection in parallel.

        Returns a list of up to ``num_cursors`` cursors that can be iterated
        concurrently. As long as the collection is not modified during
        scanning, each document appears once in one of the cursors result
        sets.

        For example, to process each document in a collection using some
        thread-safe ``process_document()`` function:

          >>> def process_cursor(cursor):
          ...     for document in cursor:
          ...     # Some thread-safe processing function:
          ...     process_document(document)
          >>>
          >>> # Get up to 4 cursors.
          ...
          >>> cursors = collection.parallel_scan(4)
          >>> threads = [
          ...     threading.Thread(target=process_cursor, args=(cursor,))
          ...     for cursor in cursors]
          >>>
          >>> for thread in threads:
          ...     thread.start()
          >>>
          >>> for thread in threads:
          ...     thread.join()
          >>>
          >>> # All documents have now been processed.

        The :meth:`parallel_scan` method obeys the :attr:`read_preference` of
        this :class:`Collection`.

        :Parameters:
          - `num_cursors`: the number of cursors to return
          - `**kwargs`: additional options for the parallelCollectionScan
            command can be passed as keyword arguments.

        .. note:: Requires server version **>= 2.5.5**.

        .. versionchanged:: 3.4
           Added back support for arbitrary keyword arguments. MongoDB 3.4
           adds support for maxTimeMS as an option to the
           parallelCollectionScan command.

        .. versionchanged:: 3.0
           Removed support for arbitrary keyword arguments, since
           the parallelCollectionScan command has no optional arguments.
        """
        cmd = SON([('parallelCollectionScan', self.__name),
                   ('numCursors', num_cursors)])
        cmd.update(kwargs)

        with self._socket_for_reads() as (sock_info, slave_ok):
            result = self._command(sock_info, cmd, slave_ok,
                                   read_concern=self.read_concern)

        return [CommandCursor(self, cursor['cursor'], sock_info.address)
                for cursor in result['cursors']]

    def _count(self, cmd, collation=None):
        """Internal count helper."""
        with self._socket_for_reads() as (sock_info, slave_ok):
            res = self._command(
                sock_info, cmd, slave_ok,
                allowable_errors=["ns missing"],
                codec_options=self.__write_response_codec_options,
                read_concern=self.read_concern,
                collation=collation)
        if res.get("errmsg", "") == "ns missing":
            return 0
        return int(res["n"])

    def count(self, filter=None, **kwargs):
        """Get the number of documents in this collection.

        All optional count parameters should be passed as keyword arguments
        to this method. Valid options include:

          - `hint` (string or list of tuples): The index to use. Specify either
            the index name as a string or the index specification as a list of
            tuples (e.g. [('a', pymongo.ASCENDING), ('b', pymongo.ASCENDING)]).
          - `limit` (int): The maximum number of documents to count.
          - `skip` (int): The number of matching documents to skip before
            returning results.
          - `maxTimeMS` (int): The maximum amount of time to allow the count
            command to run, in milliseconds.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only supported
            on MongoDB 3.4 and above.

        The :meth:`count` method obeys the :attr:`read_preference` of
        this :class:`Collection`.

        :Parameters:
          - `filter` (optional): A query document that selects which documents
            to count in the collection.
          - `**kwargs` (optional): See list of options above.

        .. versionchanged:: 3.4
           Support the `collation` option.

        """
        cmd = SON([("count", self.__name)])
        if filter is not None:
            if "query" in kwargs:
                raise ConfigurationError("can't pass both filter and query")
            kwargs["query"] = filter
        if "hint" in kwargs and not isinstance(kwargs["hint"], string_type):
            kwargs["hint"] = helpers._index_document(kwargs["hint"])
        collation = validate_collation_or_none(kwargs.pop('collation', None))
        cmd.update(kwargs)
        return self._count(cmd, collation)

    def create_indexes(self, indexes):
        """Create one or more indexes on this collection.

          >>> from pymongo import IndexModel, ASCENDING, DESCENDING
          >>> index1 = IndexModel([("hello", DESCENDING),
          ...                      ("world", ASCENDING)], name="hello_world")
          >>> index2 = IndexModel([("goodbye", DESCENDING)])
          >>> db.test.create_indexes([index1, index2])
          ["hello_world"]

        :Parameters:
          - `indexes`: A list of :class:`~pymongo.operations.IndexModel`
            instances.

        .. note:: `create_indexes` uses the ``createIndexes`` command
           introduced in MongoDB **2.6** and cannot be used with earlier
           versions.

        .. note:: The :attr:`~pymongo.collection.Collection.write_concern` of
           this collection is automatically applied to this operation when using
           MongoDB >= 3.4.

        .. versionchanged:: 3.4
           Apply this collection's write concern automatically to this operation
           when connected to MongoDB >= 3.4.
        .. versionadded:: 3.0
        """
        if not isinstance(indexes, list):
            raise TypeError("indexes must be a list")
        names = []
        def gen_indexes():
            for index in indexes:
                if not isinstance(index, IndexModel):
                    raise TypeError("%r is not an instance of "
                                    "pymongo.operations.IndexModel" % (index,))
                document = index.document
                names.append(document["name"])
                yield document
        cmd = SON([('createIndexes', self.name),
                   ('indexes', list(gen_indexes()))])
        with self._socket_for_writes() as sock_info:
            self._command(
                sock_info, cmd, read_preference=ReadPreference.PRIMARY,
                codec_options=_UNICODE_REPLACE_CODEC_OPTIONS,
                write_concern=self.write_concern,
                parse_write_concern_error=True)
        return names

    def __create_index(self, keys, index_options):
        """Internal create index helper.

        :Parameters:
          - `keys`: a list of tuples [(key, type), (key, type), ...]
          - `index_options`: a dict of index options.
        """
        index_doc = helpers._index_document(keys)
        index = {"key": index_doc}
        collation = validate_collation_or_none(
            index_options.pop('collation', None))
        index.update(index_options)

        with self._socket_for_writes() as sock_info:
            if collation is not None:
                if sock_info.max_wire_version < 5:
                    raise ConfigurationError(
                        'Must be connected to MongoDB 3.4+ to use collations.')
                else:
                    index['collation'] = collation
            cmd = SON([('createIndexes', self.name), ('indexes', [index])])
            try:
                self._command(
                    sock_info, cmd, read_preference=ReadPreference.PRIMARY,
                    codec_options=_UNICODE_REPLACE_CODEC_OPTIONS,
                    write_concern=self.write_concern,
                    parse_write_concern_error=True)
            except OperationFailure as exc:
                if exc.code in common.COMMAND_NOT_FOUND_CODES:
                    index["ns"] = self.__full_name
                    wcn = (self.write_concern if
                           self.write_concern.acknowledged else WriteConcern())
                    self.__database.system.indexes._insert(
                        sock_info, index, True, False, False, wcn)
                else:
                    raise

    def create_index(self, keys, **kwargs):
        """Creates an index on this collection.

        Takes either a single key or a list of (key, direction) pairs.
        The key(s) must be an instance of :class:`basestring`
        (:class:`str` in python 3), and the direction(s) must be one of
        (:data:`~pymongo.ASCENDING`, :data:`~pymongo.DESCENDING`,
        :data:`~pymongo.GEO2D`, :data:`~pymongo.GEOHAYSTACK`,
        :data:`~pymongo.GEOSPHERE`, :data:`~pymongo.HASHED`,
        :data:`~pymongo.TEXT`).

        To create a single key ascending index on the key ``'mike'`` we just
        use a string argument::

          >>> my_collection.create_index("mike")

        For a compound index on ``'mike'`` descending and ``'eliot'``
        ascending we need to use a list of tuples::

          >>> my_collection.create_index([("mike", pymongo.DESCENDING),
          ...                             ("eliot", pymongo.ASCENDING)])

        All optional index creation parameters should be passed as
        keyword arguments to this method. For example::

          >>> my_collection.create_index([("mike", pymongo.DESCENDING)],
          ...                            background=True)

        Valid options include, but are not limited to:

          - `name`: custom name to use for this index - if none is
            given, a name will be generated.
          - `unique`: if ``True`` creates a uniqueness constraint on the index.
          - `background`: if ``True`` this index should be created in the
            background.
          - `sparse`: if ``True``, omit from the index any documents that lack
            the indexed field.
          - `bucketSize`: for use with geoHaystack indexes.
            Number of documents to group together within a certain proximity
            to a given longitude and latitude.
          - `min`: minimum value for keys in a :data:`~pymongo.GEO2D`
            index.
          - `max`: maximum value for keys in a :data:`~pymongo.GEO2D`
            index.
          - `expireAfterSeconds`: <int> Used to create an expiring (TTL)
            collection. MongoDB will automatically delete documents from
            this collection after <int> seconds. The indexed field must
            be a UTC datetime or the data will not expire.
          - `partialFilterExpression`: A document that specifies a filter for
            a partial index.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only supported
            on MongoDB 3.4 and above.

        See the MongoDB documentation for a full list of supported options by
        server version.

        .. warning:: `dropDups` is not supported by MongoDB 3.0 or newer. The
          option is silently ignored by the server and unique index builds
          using the option will fail if a duplicate value is detected.

        .. note:: `partialFilterExpression` requires server version **>= 3.2**

        .. note:: The :attr:`~pymongo.collection.Collection.write_concern` of
           this collection is automatically applied to this operation when using
           MongoDB >= 3.4.

        :Parameters:
          - `keys`: a single key or a list of (key, direction)
            pairs specifying the index to create
          - `**kwargs` (optional): any additional index creation
            options (see the above list) should be passed as keyword
            arguments

        .. versionchanged:: 3.4
           Apply this collection's write concern automatically to this operation
           when connected to MongoDB >= 3.4. Support the `collation` option.
        .. versionchanged:: 3.2
            Added partialFilterExpression to support partial indexes.
        .. versionchanged:: 3.0
            Renamed `key_or_list` to `keys`. Removed the `cache_for` option.
            :meth:`create_index` no longer caches index names. Removed support
            for the drop_dups and bucket_size aliases.

        .. mongodoc:: indexes
        """
        keys = helpers._index_list(keys)
        name = kwargs.setdefault("name", helpers._gen_index_name(keys))
        self.__create_index(keys, kwargs)
        return name

    def ensure_index(self, key_or_list, cache_for=300, **kwargs):
        """**DEPRECATED** - Ensures that an index exists on this collection.

        .. versionchanged:: 3.0
            **DEPRECATED**
        """
        warnings.warn("ensure_index is deprecated. Use create_index instead.",
                      DeprecationWarning, stacklevel=2)
        # The types supported by datetime.timedelta.
        if not (isinstance(cache_for, integer_types) or
                isinstance(cache_for, float)):
            raise TypeError("cache_for must be an integer or float.")

        if "drop_dups" in kwargs:
            kwargs["dropDups"] = kwargs.pop("drop_dups")

        if "bucket_size" in kwargs:
            kwargs["bucketSize"] = kwargs.pop("bucket_size")

        keys = helpers._index_list(key_or_list)
        name = kwargs.setdefault("name", helpers._gen_index_name(keys))

        # Note that there is a race condition here. One thread could
        # check if the index is cached and be preempted before creating
        # and caching the index. This means multiple threads attempting
        # to create the same index concurrently could send the index
        # to the server two or more times. This has no practical impact
        # other than wasted round trips.
        if not self.__database.client._cached(self.__database.name,
                                              self.__name, name):
            self.__create_index(keys, kwargs)
            self.__database.client._cache_index(self.__database.name,
                                                self.__name, name, cache_for)
            return name
        return None

    def drop_indexes(self):
        """Drops all indexes on this collection.

        Can be used on non-existant collections or collections with no indexes.
        Raises OperationFailure on an error.

        .. note:: The :attr:`~pymongo.collection.Collection.write_concern` of
           this collection is automatically applied to this operation when using
           MongoDB >= 3.4.

        .. versionchanged:: 3.4
           Apply this collection's write concern automatically to this operation
           when connected to MongoDB >= 3.4.

        """
        self.__database.client._purge_index(self.__database.name, self.__name)
        self.drop_index("*")

    def drop_index(self, index_or_name):
        """Drops the specified index on this collection.

        Can be used on non-existant collections or collections with no
        indexes.  Raises OperationFailure on an error (e.g. trying to
        drop an index that does not exist). `index_or_name`
        can be either an index name (as returned by `create_index`),
        or an index specifier (as passed to `create_index`). An index
        specifier should be a list of (key, direction) pairs. Raises
        TypeError if index is not an instance of (str, unicode, list).

        .. warning::

          if a custom name was used on index creation (by
          passing the `name` parameter to :meth:`create_index` or
          :meth:`ensure_index`) the index **must** be dropped by name.

        :Parameters:
          - `index_or_name`: index (or name of index) to drop

        .. note:: The :attr:`~pymongo.collection.Collection.write_concern` of
           this collection is automatically applied to this operation when using
           MongoDB >= 3.4.

        .. versionchanged:: 3.4
           Apply this collection's write concern automatically to this operation
           when connected to MongoDB >= 3.4.

        """
        name = index_or_name
        if isinstance(index_or_name, list):
            name = helpers._gen_index_name(index_or_name)

        if not isinstance(name, string_type):
            raise TypeError("index_or_name must be an index name or list")

        self.__database.client._purge_index(
            self.__database.name, self.__name, name)
        cmd = SON([("dropIndexes", self.__name), ("index", name)])
        with self._socket_for_writes() as sock_info:
            self._command(sock_info,
                          cmd,
                          read_preference=ReadPreference.PRIMARY,
                          allowable_errors=["ns not found"],
                          write_concern=self.write_concern,
                          parse_write_concern_error=True)

    def reindex(self):
        """Rebuilds all indexes on this collection.

        .. warning:: reindex blocks all other operations (indexes
           are built in the foreground) and will be slow for large
           collections.

        .. note:: The :attr:`~pymongo.collection.Collection.write_concern` of
           this collection is automatically applied to this operation when using
           MongoDB >= 3.4.

        .. versionchanged:: 3.4
           Apply this collection's write concern automatically to this operation
           when connected to MongoDB >= 3.4.

        """
        cmd = SON([("reIndex", self.__name)])
        with self._socket_for_writes() as sock_info:
            return self._command(
                sock_info, cmd, read_preference=ReadPreference.PRIMARY,
                write_concern=self.write_concern,
                parse_write_concern_error=True)

    def list_indexes(self):
        """Get a cursor over the index documents for this collection.

          >>> for index in db.test.list_indexes():
          ...     print(index)
          ...
          SON([(u'v', 1), (u'key', SON([(u'_id', 1)])),
               (u'name', u'_id_'), (u'ns', u'test.test')])

        :Returns:
          An instance of :class:`~pymongo.command_cursor.CommandCursor`.

        .. versionadded:: 3.0
        """
        codec_options = CodecOptions(SON)
        coll = self.with_options(codec_options)
        with self._socket_for_primary_reads() as (sock_info, slave_ok):
            cmd = SON([("listIndexes", self.__name), ("cursor", {})])
            if sock_info.max_wire_version > 2:
                cursor = self._command(sock_info, cmd, slave_ok,
                                       ReadPreference.PRIMARY,
                                       codec_options)["cursor"]
                return CommandCursor(coll, cursor, sock_info.address)
            else:
                namespace = _UJOIN % (self.__database.name, "system.indexes")
                res = helpers._first_batch(
                    sock_info, self.__database.name, "system.indexes",
                    {"ns": self.__full_name}, 0, slave_ok, codec_options,
                    ReadPreference.PRIMARY, cmd,
                    self.database.client._event_listeners)
                data = res["data"]
                cursor = {
                    "id": res["cursor_id"],
                    "firstBatch": data,
                    "ns": namespace,
                }
                # Note that a collection can only have 64 indexes, so we don't
                # technically have to pass len(data) here. There will never be
                # an OP_GET_MORE call.
                return CommandCursor(
                    coll, cursor, sock_info.address, len(data))

    def index_information(self):
        """Get information on this collection's indexes.

        Returns a dictionary where the keys are index names (as
        returned by create_index()) and the values are dictionaries
        containing information about each index. The dictionary is
        guaranteed to contain at least a single key, ``"key"`` which
        is a list of (key, direction) pairs specifying the index (as
        passed to create_index()). It will also contain any other
        metadata about the indexes, except for the ``"ns"`` and
        ``"name"`` keys, which are cleaned. Example output might look
        like this:

        >>> db.test.ensure_index("x", unique=True)
        u'x_1'
        >>> db.test.index_information()
        {u'_id_': {u'key': [(u'_id', 1)]},
         u'x_1': {u'unique': True, u'key': [(u'x', 1)]}}
        """
        cursor = self.list_indexes()
        info = {}
        for index in cursor:
            index["key"] = index["key"].items()
            index = dict(index)
            info[index.pop("name")] = index
        return info

    def options(self):
        """Get the options set on this collection.

        Returns a dictionary of options and their values - see
        :meth:`~pymongo.database.Database.create_collection` for more
        information on the possible options. Returns an empty
        dictionary if the collection has not been created yet.
        """
        with self._socket_for_primary_reads() as (sock_info, slave_ok):
            if sock_info.max_wire_version > 2:
                criteria = {"name": self.__name}
            else:
                criteria = {"name": self.__full_name}
            cursor = self.__database._list_collections(sock_info,
                                                       slave_ok,
                                                       criteria)

        result = None
        for doc in cursor:
            result = doc
            break

        if not result:
            return {}

        options = result.get("options", {})
        if "create" in options:
            del options["create"]

        return options

    def aggregate(self, pipeline, **kwargs):
        """Perform an aggregation using the aggregation framework on this
        collection.

        All optional aggregate parameters should be passed as keyword arguments
        to this method. Valid options include, but are not limited to:

          - `allowDiskUse` (bool): Enables writing to temporary files. When set
            to True, aggregation stages can write data to the _tmp subdirectory
            of the --dbpath directory. The default is False.
          - `maxTimeMS` (int): The maximum amount of time to allow the operation
            to run in milliseconds.
          - `batchSize` (int): The maximum number of documents to return per
            batch. Ignored if the connected mongod or mongos does not support
            returning aggregate results using a cursor, or `useCursor` is
            ``False``.
          - `useCursor` (bool): Requests that the `server` provide results
            using a cursor, if possible. Ignored if the connected mongod or
            mongos does not support returning aggregate results using a cursor.
            The default is ``True``. Set this to ``False`` when upgrading a 2.4
            or older sharded cluster to 2.6 or newer (see the warning below).
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only supported
            on MongoDB 3.4 and above.

        The :meth:`aggregate` method obeys the :attr:`read_preference` of this
        :class:`Collection`. Please note that using the ``$out`` pipeline stage
        requires a read preference of
        :attr:`~pymongo.read_preferences.ReadPreference.PRIMARY` (the default).
        The server will raise an error if the ``$out`` pipeline stage is used
        with any other read preference.

        .. warning:: When upgrading a 2.4 or older sharded cluster to 2.6 or
           newer the `useCursor` option **must** be set to ``False``
           until all shards have been upgraded to 2.6 or newer.

        .. note:: This method does not support the 'explain' option. Please
           use :meth:`~pymongo.database.Database.command` instead. An
           example is included in the :ref:`aggregate-examples` documentation.

        .. note:: The :attr:`~pymongo.collection.Collection.write_concern` of
           this collection is automatically applied to this operation when using
           MongoDB >= 3.4.

        :Parameters:
          - `pipeline`: a list of aggregation pipeline stages
          - `**kwargs` (optional): See list of options above.

        :Returns:
          A :class:`~pymongo.command_cursor.CommandCursor` over the result
          set.

        .. versionchanged:: 3.4
           Apply this collection's write concern automatically to this operation
           when connected to MongoDB >= 3.4. Support the `collation` option.
        .. versionchanged:: 3.0
           The :meth:`aggregate` method always returns a CommandCursor. The
           pipeline argument must be a list.
        .. versionchanged:: 2.7
           When the cursor option is used, return
           :class:`~pymongo.command_cursor.CommandCursor` instead of
           :class:`~pymongo.cursor.Cursor`.
        .. versionchanged:: 2.6
           Added cursor support.
        .. versionadded:: 2.3

        .. seealso:: :doc:`/examples/aggregation`

        .. _aggregate command:
            http://docs.mongodb.org/manual/applications/aggregation
        """
        if not isinstance(pipeline, list):
            raise TypeError("pipeline must be a list")

        if "explain" in kwargs:
            raise ConfigurationError("The explain option is not supported. "
                                     "Use Database.command instead.")
        collation = validate_collation_or_none(kwargs.pop('collation', None))

        cmd = SON([("aggregate", self.__name),
                   ("pipeline", pipeline)])

        # Remove things that are not command options.
        batch_size = common.validate_positive_integer_or_none(
            "batchSize", kwargs.pop("batchSize", None))
        use_cursor = common.validate_boolean(
            "useCursor", kwargs.pop("useCursor", True))
        # If the server does not support the "cursor" option we
        # ignore useCursor and batchSize.
        with self._socket_for_reads() as (sock_info, slave_ok):
            if sock_info.max_wire_version > 0:
                if use_cursor:
                    if "cursor" not in kwargs:
                        kwargs["cursor"] = {}
                    if batch_size is not None:
                        kwargs["cursor"]["batchSize"] = batch_size

            dollar_out = pipeline and '$out' in pipeline[-1]
            if (sock_info.max_wire_version >= 5 and dollar_out and
                    self.write_concern):
                cmd['writeConcern'] = self.write_concern.document

            cmd.update(kwargs)

            # Apply this Collection's read concern if $out is not in the
            # pipeline.
            if sock_info.max_wire_version >= 4 and 'readConcern' not in cmd:
                if dollar_out:
                    result = self._command(sock_info, cmd, slave_ok,
                                           parse_write_concern_error=True,
                                           collation=collation)
                else:
                    result = self._command(sock_info, cmd, slave_ok,
                                           read_concern=self.read_concern,
                                           collation=collation)
            else:
                result = self._command(sock_info, cmd, slave_ok,
                                       parse_write_concern_error=dollar_out,
                                       collation=collation)

            if "cursor" in result:
                cursor = result["cursor"]
            else:
                # Pre-MongoDB 2.6. Fake a cursor.
                cursor = {
                    "id": 0,
                    "firstBatch": result["result"],
                    "ns": self.full_name,
                }
            return CommandCursor(
                self, cursor, sock_info.address).batch_size(batch_size or 0)

    # key and condition ought to be optional, but deprecation
    # would be painful as argument order would have to change.
    def group(self, key, condition, initial, reduce, finalize=None, **kwargs):
        """Perform a query similar to an SQL *group by* operation.

        Returns an array of grouped items.

        The `key` parameter can be:

          - ``None`` to use the entire document as a key.
          - A :class:`list` of keys (each a :class:`basestring`
            (:class:`str` in python 3)) to group by.
          - A :class:`basestring` (:class:`str` in python 3), or
            :class:`~bson.code.Code` instance containing a JavaScript
            function to be applied to each document, returning the key
            to group by.

        The :meth:`group` method obeys the :attr:`read_preference` of this
        :class:`Collection`.

        :Parameters:
          - `key`: fields to group by (see above description)
          - `condition`: specification of rows to be
            considered (as a :meth:`find` query specification)
          - `initial`: initial value of the aggregation counter object
          - `reduce`: aggregation function as a JavaScript string
          - `finalize`: function to be called on each object in output list.
          - `**kwargs` (optional): additional arguments to the group command
            may be passed as keyword arguments to this helper method

        .. versionchanged:: 3.4
           Added the `collation` option.
        .. versionchanged:: 2.2
           Removed deprecated argument: command
        """
        group = {}
        if isinstance(key, string_type):
            group["$keyf"] = Code(key)
        elif key is not None:
            group = {"key": helpers._fields_list_to_dict(key, "key")}
        group["ns"] = self.__name
        group["$reduce"] = Code(reduce)
        group["cond"] = condition
        group["initial"] = initial
        if finalize is not None:
            group["finalize"] = Code(finalize)

        cmd = SON([("group", group)])
        collation = validate_collation_or_none(kwargs.pop('collation', None))
        cmd.update(kwargs)

        with self._socket_for_reads() as (sock_info, slave_ok):
            return self._command(sock_info, cmd, slave_ok,
                                 collation=collation)["retval"]

    def rename(self, new_name, **kwargs):
        """Rename this collection.

        If operating in auth mode, client must be authorized as an
        admin to perform this operation. Raises :class:`TypeError` if
        `new_name` is not an instance of :class:`basestring`
        (:class:`str` in python 3). Raises :class:`~pymongo.errors.InvalidName`
        if `new_name` is not a valid collection name.

        :Parameters:
          - `new_name`: new name for this collection
          - `**kwargs` (optional): additional arguments to the rename command
            may be passed as keyword arguments to this helper method
            (i.e. ``dropTarget=True``)

        .. note:: The :attr:`~pymongo.collection.Collection.write_concern` of
           this collection is automatically applied to this operation when using
           MongoDB >= 3.4.

        .. versionchanged:: 3.4
           Apply this collection's write concern automatically to this operation
           when connected to MongoDB >= 3.4.

        """
        if not isinstance(new_name, string_type):
            raise TypeError("new_name must be an "
                            "instance of %s" % (string_type.__name__,))

        if not new_name or ".." in new_name:
            raise InvalidName("collection names cannot be empty")
        if new_name[0] == "." or new_name[-1] == ".":
            raise InvalidName("collecion names must not start or end with '.'")
        if "$" in new_name and not new_name.startswith("oplog.$main"):
            raise InvalidName("collection names must not contain '$'")

        new_name = "%s.%s" % (self.__database.name, new_name)
        cmd = SON([("renameCollection", self.__full_name), ("to", new_name)])
        with self._socket_for_writes() as sock_info:
            if sock_info.max_wire_version >= 5 and self.write_concern:
                cmd['writeConcern'] = self.write_concern.document
            cmd.update(kwargs)
            sock_info.command('admin', cmd, parse_write_concern_error=True)

    def distinct(self, key, filter=None, **kwargs):
        """Get a list of distinct values for `key` among all documents
        in this collection.

        Raises :class:`TypeError` if `key` is not an instance of
        :class:`basestring` (:class:`str` in python 3).

        All optional distinct parameters should be passed as keyword arguments
        to this method. Valid options include:

          - `maxTimeMS` (int): The maximum amount of time to allow the count
            command to run, in milliseconds.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only supported
            on MongoDB 3.4 and above.

        The :meth:`distinct` method obeys the :attr:`read_preference` of
        this :class:`Collection`.

        :Parameters:
          - `key`: name of the field for which we want to get the distinct
            values
          - `filter` (optional): A query document that specifies the documents
            from which to retrieve the distinct values.
          - `**kwargs` (optional): See list of options above.

        .. versionchanged:: 3.4
           Support the `collation` option.

        """
        if not isinstance(key, string_type):
            raise TypeError("key must be an "
                            "instance of %s" % (string_type.__name__,))
        cmd = SON([("distinct", self.__name),
                   ("key", key)])
        if filter is not None:
            if "query" in kwargs:
                raise ConfigurationError("can't pass both filter and query")
            kwargs["query"] = filter
        collation = validate_collation_or_none(kwargs.pop('collation', None))
        cmd.update(kwargs)
        with self._socket_for_reads() as (sock_info, slave_ok):
            return self._command(sock_info, cmd, slave_ok,
                                 read_concern=self.read_concern,
                                 collation=collation)["values"]

    def map_reduce(self, map, reduce, out, full_response=False, **kwargs):
        """Perform a map/reduce operation on this collection.

        If `full_response` is ``False`` (default) returns a
        :class:`~pymongo.collection.Collection` instance containing
        the results of the operation. Otherwise, returns the full
        response from the server to the `map reduce command`_.

        :Parameters:
          - `map`: map function (as a JavaScript string)
          - `reduce`: reduce function (as a JavaScript string)
          - `out`: output collection name or `out object` (dict). See
            the `map reduce command`_ documentation for available options.
            Note: `out` options are order sensitive. :class:`~bson.son.SON`
            can be used to specify multiple options.
            e.g. SON([('replace', <collection name>), ('db', <database name>)])
          - `full_response` (optional): if ``True``, return full response to
            this command - otherwise just return the result collection
          - `**kwargs` (optional): additional arguments to the
            `map reduce command`_ may be passed as keyword arguments to this
            helper method, e.g.::

            >>> db.test.map_reduce(map, reduce, "myresults", limit=2)

        .. note:: The :meth:`map_reduce` method does **not** obey the
           :attr:`read_preference` of this :class:`Collection`. To run
           mapReduce on a secondary use the :meth:`inline_map_reduce` method
           instead.

        .. note:: The :attr:`~pymongo.collection.Collection.write_concern` of
           this collection is automatically applied to this operation (if the
           output is not inline) when using MongoDB >= 3.4.

        .. versionchanged:: 3.4
           Apply this collection's write concern automatically to this operation
           when connected to MongoDB >= 3.4.

        .. seealso:: :doc:`/examples/aggregation`

        .. versionchanged:: 3.4
           Added the `collation` option.
        .. versionchanged:: 2.2
           Removed deprecated arguments: merge_output and reduce_output

        .. _map reduce command: http://docs.mongodb.org/manual/reference/command/mapReduce/

        .. mongodoc:: mapreduce

        """
        if not isinstance(out, (string_type, collections.Mapping)):
            raise TypeError("'out' must be an instance of "
                            "%s or a mapping" % (string_type.__name__,))

        cmd = SON([("mapreduce", self.__name),
                   ("map", map),
                   ("reduce", reduce),
                   ("out", out)])
        collation = validate_collation_or_none(kwargs.pop('collation', None))
        cmd.update(kwargs)

        inline = 'inline' in cmd['out']
        with self._socket_for_primary_reads() as (sock_info, slave_ok):
            if (sock_info.max_wire_version >= 5 and self.write_concern and
                    not inline):
                cmd['writeConcern'] = self.write_concern.document
            cmd.update(kwargs)
            if (sock_info.max_wire_version >= 4 and 'readConcern' not in cmd and
                    inline):
                # No need to parse 'writeConcernError' here, since the command
                # is an inline map reduce.
                response = self._command(
                    sock_info, cmd, slave_ok, ReadPreference.PRIMARY,
                    read_concern=self.read_concern,
                    collation=collation)
            else:
                response = self._command(
                    sock_info, cmd, slave_ok, ReadPreference.PRIMARY,
                    parse_write_concern_error=not inline,
                    collation=collation)

        if full_response or not response.get('result'):
            return response
        elif isinstance(response['result'], dict):
            dbase = response['result']['db']
            coll = response['result']['collection']
            return self.__database.client[dbase][coll]
        else:
            return self.__database[response["result"]]

    def inline_map_reduce(self, map, reduce, full_response=False, **kwargs):
        """Perform an inline map/reduce operation on this collection.

        Perform the map/reduce operation on the server in RAM. A result
        collection is not created. The result set is returned as a list
        of documents.

        If `full_response` is ``False`` (default) returns the
        result documents in a list. Otherwise, returns the full
        response from the server to the `map reduce command`_.

        The :meth:`inline_map_reduce` method obeys the :attr:`read_preference`
        of this :class:`Collection`.

        :Parameters:
          - `map`: map function (as a JavaScript string)
          - `reduce`: reduce function (as a JavaScript string)
          - `full_response` (optional): if ``True``, return full response to
            this command - otherwise just return the result collection
          - `**kwargs` (optional): additional arguments to the
            `map reduce command`_ may be passed as keyword arguments to this
            helper method, e.g.::

            >>> db.test.inline_map_reduce(map, reduce, limit=2)

        .. versionchanged:: 3.4
           Added the `collation` option.

        """
        cmd = SON([("mapreduce", self.__name),
                   ("map", map),
                   ("reduce", reduce),
                   ("out", {"inline": 1})])
        collation = validate_collation_or_none(kwargs.pop('collation', None))
        cmd.update(kwargs)
        with self._socket_for_reads() as (sock_info, slave_ok):
            if sock_info.max_wire_version >= 4 and 'readConcern' not in cmd:
                res = self._command(sock_info, cmd, slave_ok,
                                    read_concern=self.read_concern,
                                    collation=collation)
            else:
                res = self._command(sock_info, cmd, slave_ok,
                                    collation=collation)

        if full_response:
            return res
        else:
            return res.get("results")

    def __find_and_modify(self, filter, projection, sort, upsert=None,
                          return_document=ReturnDocument.BEFORE, **kwargs):
        """Internal findAndModify helper."""
        common.validate_is_mapping("filter", filter)
        if not isinstance(return_document, bool):
            raise ValueError("return_document must be "
                             "ReturnDocument.BEFORE or ReturnDocument.AFTER")
        collation = validate_collation_or_none(kwargs.pop('collation', None))
        cmd = SON([("findAndModify", self.__name),
                   ("query", filter),
                   ("new", return_document)])
        cmd.update(kwargs)
        if projection is not None:
            cmd["fields"] = helpers._fields_list_to_dict(projection,
                                                         "projection")
        if sort is not None:
            cmd["sort"] = helpers._index_document(sort)
        if upsert is not None:
            common.validate_boolean("upsert", upsert)
            cmd["upsert"] = upsert
        with self._socket_for_writes() as sock_info:
            if sock_info.max_wire_version >= 4 and 'writeConcern' not in cmd:
                wc_doc = self.write_concern.document
                if wc_doc:
                    cmd['writeConcern'] = wc_doc
            out = self._command(sock_info, cmd,
                                read_preference=ReadPreference.PRIMARY,
                                allowable_errors=[_NO_OBJ_ERROR],
                                collation=collation)
            _check_write_command_response([(0, out)])
        return out.get("value")

    def find_one_and_delete(self, filter,
                            projection=None, sort=None, **kwargs):
        """Finds a single document and deletes it, returning the document.

          >>> db.test.count({'x': 1})
          2
          >>> db.test.find_one_and_delete({'x': 1})
          {u'x': 1, u'_id': ObjectId('54f4e12bfba5220aa4d6dee8')}
          >>> db.test.count({'x': 1})
          1

        If multiple documents match *filter*, a *sort* can be applied.

          >>> for doc in db.test.find({'x': 1}):
          ...     print(doc)
          ...
          {u'x': 1, u'_id': 0}
          {u'x': 1, u'_id': 1}
          {u'x': 1, u'_id': 2}
          >>> db.test.find_one_and_delete(
          ...     {'x': 1}, sort=[('_id', pymongo.DESCENDING)])
          {u'x': 1, u'_id': 2}

        The *projection* option can be used to limit the fields returned.

          >>> db.test.find_one_and_delete({'x': 1}, projection={'_id': False})
          {u'x': 1}

        :Parameters:
          - `filter`: A query that matches the document to delete.
          - `projection` (optional): a list of field names that should be
            returned in the result document or a mapping specifying the fields
            to include or exclude. If `projection` is a list "_id" will
            always be returned. Use a mapping to exclude fields from
            the result (e.g. projection={'_id': False}).
          - `sort` (optional): a list of (key, direction) pairs
            specifying the sort order for the query. If multiple documents
            match the query, they are sorted and the first is deleted.
          - `**kwargs` (optional): additional command arguments can be passed
            as keyword arguments (for example maxTimeMS can be used with
            recent server versions).

        .. versionchanged:: 3.2
           Respects write concern.

        .. warning:: Starting in PyMongo 3.2, this command uses the
           :class:`~pymongo.write_concern.WriteConcern` of this
           :class:`~pymongo.collection.Collection` when connected to MongoDB >=
           3.2. Note that using an elevated write concern with this command may
           be slower compared to using the default write concern.

        .. versionchanged:: 3.4
           Added the `collation` option.
        .. versionadded:: 3.0

        """
        kwargs['remove'] = True
        return self.__find_and_modify(filter, projection, sort, **kwargs)

    def find_one_and_replace(self, filter, replacement,
                             projection=None, sort=None, upsert=False,
                             return_document=ReturnDocument.BEFORE, **kwargs):
        """Finds a single document and replaces it, returning either the
        original or the replaced document.

        The :meth:`find_one_and_replace` method differs from
        :meth:`find_one_and_update` by replacing the document matched by
        *filter*, rather than modifying the existing document.

          >>> for doc in db.test.find({}):
          ...     print(doc)
          ...
          {u'x': 1, u'_id': 0}
          {u'x': 1, u'_id': 1}
          {u'x': 1, u'_id': 2}
          >>> db.test.find_one_and_replace({'x': 1}, {'y': 1})
          {u'x': 1, u'_id': 0}
          >>> for doc in db.test.find({}):
          ...     print(doc)
          ...
          {u'y': 1, u'_id': 0}
          {u'x': 1, u'_id': 1}
          {u'x': 1, u'_id': 2}

        :Parameters:
          - `filter`: A query that matches the document to replace.
          - `replacement`: The replacement document.
          - `projection` (optional): A list of field names that should be
            returned in the result document or a mapping specifying the fields
            to include or exclude. If `projection` is a list "_id" will
            always be returned. Use a mapping to exclude fields from
            the result (e.g. projection={'_id': False}).
          - `sort` (optional): a list of (key, direction) pairs
            specifying the sort order for the query. If multiple documents
            match the query, they are sorted and the first is replaced.
          - `upsert` (optional): When ``True``, inserts a new document if no
            document matches the query. Defaults to ``False``.
          - `return_document`: If
            :attr:`ReturnDocument.BEFORE` (the default),
            returns the original document before it was replaced, or ``None``
            if no document matches. If
            :attr:`ReturnDocument.AFTER`, returns the replaced
            or inserted document.
          - `**kwargs` (optional): additional command arguments can be passed
            as keyword arguments (for example maxTimeMS can be used with
            recent server versions).

        .. versionchanged:: 3.4
           Added the `collation` option.
        .. versionchanged:: 3.2
           Respects write concern.

        .. warning:: Starting in PyMongo 3.2, this command uses the
           :class:`~pymongo.write_concern.WriteConcern` of this
           :class:`~pymongo.collection.Collection` when connected to MongoDB >=
           3.2. Note that using an elevated write concern with this command may
           be slower compared to using the default write concern.

        .. versionadded:: 3.0
        """
        common.validate_ok_for_replace(replacement)
        kwargs['update'] = replacement
        return self.__find_and_modify(filter, projection,
                                      sort, upsert, return_document, **kwargs)

    def find_one_and_update(self, filter, update,
                            projection=None, sort=None, upsert=False,
                            return_document=ReturnDocument.BEFORE, **kwargs):
        """Finds a single document and updates it, returning either the
        original or the updated document.

          >>> db.test.find_one_and_update(
          ...    {'_id': 665}, {'$inc': {'count': 1}, '$set': {'done': True}})
          {u'_id': 665, u'done': False, u'count': 25}}

        By default :meth:`find_one_and_update` returns the original version of
        the document before the update was applied. To return the updated
        version of the document instead, use the *return_document* option.

          >>> from pymongo import ReturnDocument
          >>> db.example.find_one_and_update(
          ...     {'_id': 'userid'},
          ...     {'$inc': {'seq': 1}},
          ...     return_document=ReturnDocument.AFTER)
          {u'_id': u'userid', u'seq': 1}

        You can limit the fields returned with the *projection* option.

          >>> db.example.find_one_and_update(
          ...     {'_id': 'userid'},
          ...     {'$inc': {'seq': 1}},
          ...     projection={'seq': True, '_id': False},
          ...     return_document=ReturnDocument.AFTER)
          {u'seq': 2}

        The *upsert* option can be used to create the document if it doesn't
        already exist.

          >>> db.example.delete_many({}).deleted_count
          1
          >>> db.example.find_one_and_update(
          ...     {'_id': 'userid'},
          ...     {'$inc': {'seq': 1}},
          ...     projection={'seq': True, '_id': False},
          ...     upsert=True,
          ...     return_document=ReturnDocument.AFTER)
          {u'seq': 1}

        If multiple documents match *filter*, a *sort* can be applied.

          >>> for doc in db.test.find({'done': True}):
          ...     print(doc)
          ...
          {u'_id': 665, u'done': True, u'result': {u'count': 26}}
          {u'_id': 701, u'done': True, u'result': {u'count': 17}}
          >>> db.test.find_one_and_update(
          ...     {'done': True},
          ...     {'$set': {'final': True}},
          ...     sort=[('_id', pymongo.DESCENDING)])
          {u'_id': 701, u'done': True, u'result': {u'count': 17}}

        :Parameters:
          - `filter`: A query that matches the document to update.
          - `update`: The update operations to apply.
          - `projection` (optional): A list of field names that should be
            returned in the result document or a mapping specifying the fields
            to include or exclude. If `projection` is a list "_id" will
            always be returned. Use a dict to exclude fields from
            the result (e.g. projection={'_id': False}).
          - `sort` (optional): a list of (key, direction) pairs
            specifying the sort order for the query. If multiple documents
            match the query, they are sorted and the first is updated.
          - `upsert` (optional): When ``True``, inserts a new document if no
            document matches the query. Defaults to ``False``.
          - `return_document`: If
            :attr:`ReturnDocument.BEFORE` (the default),
            returns the original document before it was updated, or ``None``
            if no document matches. If
            :attr:`ReturnDocument.AFTER`, returns the updated
            or inserted document.
          - `**kwargs` (optional): additional command arguments can be passed
            as keyword arguments (for example maxTimeMS can be used with
            recent server versions).

        .. versionchanged:: 3.4
           Added the `collation` option.
        .. versionchanged:: 3.2
           Respects write concern.

        .. warning:: Starting in PyMongo 3.2, this command uses the
           :class:`~pymongo.write_concern.WriteConcern` of this
           :class:`~pymongo.collection.Collection` when connected to MongoDB >=
           3.2. Note that using an elevated write concern with this command may
           be slower compared to using the default write concern.

        .. versionadded:: 3.0
        """
        common.validate_ok_for_update(update)
        kwargs['update'] = update
        return self.__find_and_modify(filter, projection,
                                      sort, upsert, return_document, **kwargs)

    def save(self, to_save, manipulate=True, check_keys=True, **kwargs):
        """Save a document in this collection.

        **DEPRECATED** - Use :meth:`insert_one` or :meth:`replace_one` instead.

        .. versionchanged:: 3.0
           Removed the `safe` parameter. Pass ``w=0`` for unacknowledged write
           operations.
        """
        warnings.warn("save is deprecated. Use insert_one or replace_one "
                      "instead", DeprecationWarning, stacklevel=2)
        common.validate_is_document_type("to_save", to_save)

        write_concern = None
        collation = validate_collation_or_none(kwargs.pop('collation', None))
        if kwargs:
            write_concern = WriteConcern(**kwargs)

        with self._socket_for_writes() as sock_info:
            if not (isinstance(to_save, RawBSONDocument) or "_id" in to_save):
                return self._insert(sock_info, to_save, True,
                                    check_keys, manipulate, write_concern)
            else:
                self._update(sock_info, {"_id": to_save["_id"]}, to_save, True,
                             check_keys, False, manipulate, write_concern,
                             collation=collation)
                return to_save.get("_id")

    def insert(self, doc_or_docs, manipulate=True,
               check_keys=True, continue_on_error=False, **kwargs):
        """Insert a document(s) into this collection.

        **DEPRECATED** - Use :meth:`insert_one` or :meth:`insert_many` instead.

        .. versionchanged:: 3.0
           Removed the `safe` parameter. Pass ``w=0`` for unacknowledged write
           operations.
        """
        warnings.warn("insert is deprecated. Use insert_one or insert_many "
                      "instead.", DeprecationWarning, stacklevel=2)
        write_concern = None
        if kwargs:
            write_concern = WriteConcern(**kwargs)
        with self._socket_for_writes() as sock_info:
            return self._insert(sock_info, doc_or_docs, not continue_on_error,
                                check_keys, manipulate, write_concern)

    def update(self, spec, document, upsert=False, manipulate=False,
               multi=False, check_keys=True, **kwargs):
        """Update a document(s) in this collection.

        **DEPRECATED** - Use :meth:`replace_one`, :meth:`update_one`, or
        :meth:`update_many` instead.

        .. versionchanged:: 3.0
           Removed the `safe` parameter. Pass ``w=0`` for unacknowledged write
           operations.
        """
        warnings.warn("update is deprecated. Use replace_one, update_one or "
                      "update_many instead.", DeprecationWarning, stacklevel=2)
        common.validate_is_mapping("spec", spec)
        common.validate_is_mapping("document", document)
        if document:
            # If a top level key begins with '$' this is a modify operation
            # and we should skip key validation. It doesn't matter which key
            # we check here. Passing a document with a mix of top level keys
            # starting with and without a '$' is invalid and the server will
            # raise an appropriate exception.
            first = next(iter(document))
            if first.startswith('$'):
                check_keys = False

        write_concern = None
        collation = validate_collation_or_none(kwargs.pop('collation', None))
        if kwargs:
            write_concern = WriteConcern(**kwargs)
        with self._socket_for_writes() as sock_info:
            return self._update(sock_info, spec, document, upsert,
                                check_keys, multi, manipulate, write_concern,
                                collation=collation)

    def remove(self, spec_or_id=None, multi=True, **kwargs):
        """Remove a document(s) from this collection.

        **DEPRECATED** - Use :meth:`delete_one` or :meth:`delete_many` instead.

        .. versionchanged:: 3.0
           Removed the `safe` parameter. Pass ``w=0`` for unacknowledged write
           operations.
        """
        warnings.warn("remove is deprecated. Use delete_one or delete_many "
                      "instead.", DeprecationWarning, stacklevel=2)
        if spec_or_id is None:
            spec_or_id = {}
        if not isinstance(spec_or_id, collections.Mapping):
            spec_or_id = {"_id": spec_or_id}
        write_concern = None
        collation = validate_collation_or_none(kwargs.pop('collation', None))
        if kwargs:
            write_concern = WriteConcern(**kwargs)
        with self._socket_for_writes() as sock_info:
            return self._delete(sock_info, spec_or_id, multi, write_concern,
                                collation=collation)

    def find_and_modify(self, query={}, update=None,
                        upsert=False, sort=None, full_response=False,
                        manipulate=False, **kwargs):
        """Update and return an object.

        **DEPRECATED** - Use :meth:`find_one_and_delete`,
        :meth:`find_one_and_replace`, or :meth:`find_one_and_update` instead.
        """
        warnings.warn("find_and_modify is deprecated, use find_one_and_delete"
                      ", find_one_and_replace, or find_one_and_update instead",
                      DeprecationWarning, stacklevel=2)

        if not update and not kwargs.get('remove', None):
            raise ValueError("Must either update or remove")

        if update and kwargs.get('remove', None):
            raise ValueError("Can't do both update and remove")

        # No need to include empty args
        if query:
            kwargs['query'] = query
        if update:
            kwargs['update'] = update
        if upsert:
            kwargs['upsert'] = upsert
        if sort:
            # Accept a list of tuples to match Cursor's sort parameter.
            if isinstance(sort, list):
                kwargs['sort'] = helpers._index_document(sort)
            # Accept OrderedDict, SON, and dict with len == 1 so we
            # don't break existing code already using find_and_modify.
            elif (isinstance(sort, _ORDERED_TYPES) or
                  isinstance(sort, dict) and len(sort) == 1):
                warnings.warn("Passing mapping types for `sort` is deprecated,"
                              " use a list of (key, direction) pairs instead",
                              DeprecationWarning, stacklevel=2)
                kwargs['sort'] = sort
            else:
                raise TypeError("sort must be a list of (key, direction) "
                                "pairs, a dict of len 1, or an instance of "
                                "SON or OrderedDict")

        fields = kwargs.pop("fields", None)
        if fields is not None:
            kwargs["fields"] = helpers._fields_list_to_dict(fields, "fields")

        collation = validate_collation_or_none(kwargs.pop('collation', None))

        cmd = SON([("findAndModify", self.__name)])
        cmd.update(kwargs)
        with self._socket_for_writes() as sock_info:
            if sock_info.max_wire_version >= 4 and 'writeConcern' not in cmd:
                wc_doc = self.write_concern.document
                if wc_doc:
                    cmd['writeConcern'] = wc_doc
            out = self._command(sock_info, cmd,
                                read_preference=ReadPreference.PRIMARY,
                                allowable_errors=[_NO_OBJ_ERROR],
                                collation=collation)
            _check_write_command_response([(0, out)])

        if not out['ok']:
            if out["errmsg"] == _NO_OBJ_ERROR:
                return None
            else:
                # Should never get here b/c of allowable_errors
                raise ValueError("Unexpected Error: %s" % (out,))

        if full_response:
            return out
        else:
            document = out.get('value')
            if manipulate:
                document = self.__database._fix_outgoing(document, self)
            return document

    def __iter__(self):
        return self

    def __next__(self):
        raise TypeError("'Collection' object is not iterable")

    next = __next__

    def __call__(self, *args, **kwargs):
        """This is only here so that some API misusages are easier to debug.
        """
        if "." not in self.__name:
            raise TypeError("'Collection' object is not callable. If you "
                            "meant to call the '%s' method on a 'Database' "
                            "object it is failing because no such method "
                            "exists." %
                            self.__name)
        raise TypeError("'Collection' object is not callable. If you meant to "
                        "call the '%s' method on a 'Collection' object it is "
                        "failing because no such method exists." %
                        self.__name.split(".")[-1])