/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/ is in calendarserver 5.2+dfsg-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/__init__.py
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/delivery.py
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/inbound.py
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/mailgateway.py
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/outbound.py
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/scheduler.py
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/smtpsender.py
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/test/
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/test/__init__.py
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/test/test_delivery.py
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/test/test_inbound.py
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/test/test_mailgateway.py
/usr/lib/python2.7/dist-packages/txdav/caldav/datastore/scheduling/imip/test/test_outbound.py