/usr/lib/python2.6/dist-packages/twill/extensions/mailman_sf.py is in python-twill 0.9-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.6/dist-packages/twill/extensions/../../../../../share/pyshared/twill/extensions/mailman_sf.py