iPM-1237 Remove dependency on plex which is not Py3 compliant.
iPM-1237 Remove dependency on plex which is not Py3 compliant.

pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus