/usr/lib/python2.7/dist-packages/twext/who/ is in calendarserver 5.2+dfsg-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/python2.7/dist-packages/twext/who/__init__.py
/usr/lib/python2.7/dist-packages/twext/who/aggregate.py
/usr/lib/python2.7/dist-packages/twext/who/directory.py
/usr/lib/python2.7/dist-packages/twext/who/expression.py
/usr/lib/python2.7/dist-packages/twext/who/idirectory.py
/usr/lib/python2.7/dist-packages/twext/who/index.py
/usr/lib/python2.7/dist-packages/twext/who/test/
/usr/lib/python2.7/dist-packages/twext/who/test/__init__.py
/usr/lib/python2.7/dist-packages/twext/who/test/test_aggregate.py
/usr/lib/python2.7/dist-packages/twext/who/test/test_directory.py
/usr/lib/python2.7/dist-packages/twext/who/test/test_expression.py
/usr/lib/python2.7/dist-packages/twext/who/test/test_util.py
/usr/lib/python2.7/dist-packages/twext/who/test/test_xml.py
/usr/lib/python2.7/dist-packages/twext/who/util.py
/usr/lib/python2.7/dist-packages/twext/who/xml.py