/usr/lib/python2.7/dist-packages/piston/ is in python-django-piston 0.2.3-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/python2.7/dist-packages/piston/authentication.py
/usr/lib/python2.7/dist-packages/piston/doc.py
/usr/lib/python2.7/dist-packages/piston/emitters.py
/usr/lib/python2.7/dist-packages/piston/forms.py
/usr/lib/python2.7/dist-packages/piston/handler.py
/usr/lib/python2.7/dist-packages/piston/handlers_doc.py
/usr/lib/python2.7/dist-packages/piston/managers.py
/usr/lib/python2.7/dist-packages/piston/middleware.py
/usr/lib/python2.7/dist-packages/piston/models.py
/usr/lib/python2.7/dist-packages/piston/resource.py
/usr/lib/python2.7/dist-packages/piston/signals.py
/usr/lib/python2.7/dist-packages/piston/store.py
/usr/lib/python2.7/dist-packages/piston/templates/
/usr/lib/python2.7/dist-packages/piston/templates/documentation.html
/usr/lib/python2.7/dist-packages/piston/templates/piston/
/usr/lib/python2.7/dist-packages/piston/templates/piston/authorize_token.html
/usr/lib/python2.7/dist-packages/piston/test.py
/usr/lib/python2.7/dist-packages/piston/tests.py
/usr/lib/python2.7/dist-packages/piston/utils.py
/usr/lib/python2.7/dist-packages/piston/validate_jsonp.py