/usr/lib/python2.7/dist-packages/SparsExamples/poisson2dvec.py is in python-sparse-examples 1.1-1.3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.7/dist-packages/SparsExamples/../../../../share/pyshared/SparsExamples/poisson2dvec.py