Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/picard/webservice/__init__.py", line 524, in _process_reply
    self._handle_reply(reply, request)
  File "/usr/lib/python3.6/site-packages/picard/webservice/__init__.py", line 511, in _handle_reply
    handler(document, reply, error)
  File "/usr/lib/python3.6/site-packages/picard/releasegroup.py", line 147, in _request_finished
    callback()
  File "/usr/lib/python3.6/site-packages/picard/ui/itemviews.py", line 341, in _add_other_versions
    "countrymatch": "0" if len(preferred_countries) == 0 or preferred_countries & set(version['countries']) else "?",
TypeError: 'NoneType' object is not iterable
[1]    32246 abort (core dumped)  picard