/usr/lib/python2.7/dist-packages/mx/Proxy/Proxy.py is in python-egenix-mxproxy 3.2.1-1.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.7/dist-packages/mx/Proxy/../../../../../share/pyshared/mx/Proxy/Proxy.py