[DSE-Dev] Bug#896212: python3-sepolicy: sepolicy fails to import

[Helmut Grohne]

Package: python3-sepolicy
Version: 2.7-2
Severity: serious
User: helmutg at debian.org
Usertags: python-import

After installing python3-sepolicy importing the module sepolicy
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/sepolicy/__init__.py", line 8, in <module>
    import setools
  File "/usr/lib/python3/dist-packages/setools/__init__.py", line 77, in <module>
    from .infoflow import InfoFlowAnalysis
  File "/usr/lib/python3/dist-packages/setools/infoflow.py", line 22, in <module>
    import networkx as nx
  File "/usr/lib/python3/dist-packages/networkx/__init__.py", line 87, in <module>
    import networkx.readwrite
  File "/usr/lib/python3/dist-packages/networkx/readwrite/__init__.py", line 14, in <module>
    from networkx.readwrite.gml import *
  File "/usr/lib/python3/dist-packages/networkx/readwrite/gml.py", line 44, in <module>
    from lib2to3.pgen2.parse import ParseError
ModuleNotFoundError: No module named 'lib2to3'

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