Type `tag` properly

[sakgoyal]

mutagen/mutagen/_file.py

Line 39 in 9e3ff54

tags = None

Here, tag should be typed as ID3 | None = None right? (Optional[ID3] for python<3.12)

[semohr]

I had an interest in typing this too and had a look, sadly it is not that easy.

Have a look where tags are assigned, tags can be an instance of a number of different classes (all inheriting from Tags but some also inheriting from Metadata and/or DictProxy ).

E.g.:

mutagen/mutagen/m4a.py

Line 91 in 9e3ff54

self.tags = M4ATags()

mutagen/mutagen/dsdiff.py

Line 257 in 4394c43

self.tags = _DSDIFFID3()

[sakgoyal]

can't the type be overridden in those instances then?