[Python-modules-team] Bug#896202: python-subliminal: subliminal fails to import

[Helmut Grohne]

Package: python-subliminal
Version: 1.1.1-2
Severity: serious
User: helmutg at debian.org
Usertags: python-import

After installing python-subliminal importing the module subliminal
into a python interpreter fails with the following error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python2.7/dist-packages/subliminal/__init__.py", line 10, in <module>
    from .api import (ProviderPool, check_video, provider_manager, download_best_subtitles, download_subtitles,
  File "/usr/lib/python2.7/dist-packages/subliminal/api.py", line 13, in <module>
    from .subtitle import compute_score, get_subtitle_path
  File "/usr/lib/python2.7/dist-packages/subliminal/subtitle.py", line 7, in <module>
    from guessit.matchtree import MatchTree
  File "/usr/lib/python2.7/dist-packages/guessit/__init__.py", line 99, in <module>
    from guessit.plugins import transformers
  File "/usr/lib/python2.7/dist-packages/guessit/plugins/transformers.py", line 222, in <module>
    reload()
  File "/usr/lib/python2.7/dist-packages/guessit/plugins/transformers.py", line 220, in reload
    reload_options(all_transformers())
  File "/usr/lib/python2.7/dist-packages/guessit/plugins/transformers.py", line 179, in all_transformers
    return _extensions.objects()
  File "/usr/lib/python2.7/dist-packages/guessit/plugins/transformers.py", line 111, in objects
    return self.map(self._get_obj)
  File "/usr/lib/python2.7/dist-packages/stevedore/extension.py", line 261, in map
    raise NoMatches('No %s extensions found' % self.namespace)
stevedore.exception.NoMatches: No guessit.transformer extensions found

The vast majority of import failures is attributed to missing dependencies.
Often times that manifests as an ImportError or ModuleNotFoundError.
Typically, dependencies should be inserted by dh-python via ${python:Depends}
or ${python3:Depends}. Thus a missing dependency can be caused by incomplete
install_requires in setup.py. Sometimes a missing dependency of a dependency
is the cause, in such cases this bug should be reassigned.

Helmut