[6.0.0] importlib.util.find_spec raises ValueError (it was not a case with imp.find_module)

[amureki]

Greetings!
Thakns for maintaining this package! ✨

While trying new version 6.0.0, we discovered the next issue:

Exception occurred:
  File "/opt/python/3.8.6/lib/python3.8/importlib/util.py", line 114, in find_spec
    raise ValueError('{}.__spec__ is None'.format(name))
ValueError: celery.__spec__ is None

I did try to dig a bit and discovered, that new importlib.find_spec raises ValueError in case the spec would be None or is not set. The change related to it was introduced in #73.

This behaviour differs from imp.find_module, where it was returning None or raising ImportError.

Seems like we need to update this bit in spelling library to cover new behaviour.

Cheers,
Rust

[dhellmann]

The fix you've provided is included in release 7.0.0, so I'm going to close this issue. I think this is the same as #95, which I am leaving open until the reporters there can confirm that the fix also solves the problem for them.

Thanks again for finding and fixing the problem!