[Python-modules-team] Bug#896375: python3-changelog: changelog fails to import

[Helmut Grohne]

Package: python3-changelog
Version: 0.3.5-1
Severity: serious
User: helmutg at debian.org
Usertags: python-import

After installing python3-changelog importing the module changelog
into a python interpreter fails with the following error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python3/dist-packages/changelog/__init__.py", line 3, in <module>
    from .changelog import setup
  File "/usr/lib/python3/dist-packages/changelog/changelog.py", line 5, in <module>
    from sphinx.util.compat import Directive
ModuleNotFoundError: No module named 'sphinx'

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