TypeError: None not a valid annotation (since PR #260)

[mkunesch]

Hi!

I think PR #260 introduced a TypeError:

Line 86 of _common.py reads:

@resolve.register
def _(cand: None) -> types.ModuleType:

and leads to AssertionError: Invalid annotation for 'cand'. None is not a class. from this line in functools.

Is a problem with using python 3.7?
Thanks a lot!

[mkunesch]

Sorry, the code should be absolutely fine. The error only arises when running sphinx on our code - not sure why. I'm closing this while I investigate further where the issue is.