/usr/lib/python2.7/dist-packages/Pyrex/Plex/ is in python-pyrex 0.9.8.5-2ubuntu3.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/python2.7/dist-packages/Pyrex/Plex/Actions.py
/usr/lib/python2.7/dist-packages/Pyrex/Plex/DFA.py
/usr/lib/python2.7/dist-packages/Pyrex/Plex/Errors.py
/usr/lib/python2.7/dist-packages/Pyrex/Plex/Lexicons.py
/usr/lib/python2.7/dist-packages/Pyrex/Plex/Machines.py
/usr/lib/python2.7/dist-packages/Pyrex/Plex/Regexps.py
/usr/lib/python2.7/dist-packages/Pyrex/Plex/Scanners.py
/usr/lib/python2.7/dist-packages/Pyrex/Plex/Timing.py
/usr/lib/python2.7/dist-packages/Pyrex/Plex/Traditional.py
/usr/lib/python2.7/dist-packages/Pyrex/Plex/Transitions.py
/usr/lib/python2.7/dist-packages/Pyrex/Plex/__init__.py
/usr/lib/python2.7/dist-packages/Pyrex/Plex/test_tm.py