Use packaging.version in _compare_version

[cbrnr]

Fixes #10197. Do we want to move the function to a different module?

[hoechenberger]

Do we want to move the function to a different module?

Maybe somewhere inside the mne.utils namespace would be good?

[hoechenberger]

LGTM once we go green!! Thanks @cbrnr

[cbrnr]

We have a circular import here, the problem is that in check.py we from ..fixes import _median_complex, and in fixes.py we from .utils import _compare_version.

We could nicely resolve this if we get rid of the _median_complex fix, which has already been fixed upstream I think (scipy/scipy#12676). However, I think this was released in SciPy 1.7, and we currently support >= 1.4.1. I think this fix has also been backported, but I'm not sure which versions received the fix. So should we bump the minimum SciPy version, and if yes, to which version? @larsoner

[larsoner]

Let's move _compare_version back to fixes.py -- we don't want fixes.py to import from any other mne namespace for exactly this reason. It's nice to know everything in there is always safe to use with no risk of circular import

[cbrnr]

All green!

[hoechenberger]

Perfect, thanks, @cbrnr!