Make WeightsEnum public

[adamjstewart]

🚀 The feature

I propose making torchvision.models._api.WeightsEnum public and adding documentation for it.

Motivation, pitch

TorchGeo is adopting torchvision's new multi-weight support API: microsoft/torchgeo#917

All of our weights subclass WeightsEnum, but this requires us to import directly from torchvision.models._api. Since this module is prefixed by an underscore, I'm assuming this class is private and subject to change. Also, since this class isn't documented, we have to silence Sphinx warnings about the missing parent class docs.

Alternatives

We could copy-n-paste your WeightsEnum implementation but code duplication is bad and I don't want to deal with legal. We could keep importing from a private module but it may change in the future. Are there any other suggested alternatives for other libraries trying to copy the same design? Maybe this could be moved into TorchData?

Additional context

@nilsleh

[NicolasHug]

Thanks for the feature request @adamjstewart . It's great to see torchgeo adopt the same API!

I think we're open to make the Weights and WeightsEnum classes public. They might require a bit of cleanup before we can make them public, so I started doing that in #7100. Please feel free to take a look and provide feedback!

[adamjstewart]

On the topic of WeightsEnum, I noticed that there is no md5 attribute and no checksumming done when downloading weights like there is for datasets. Should there be? (I can open a separate issue for this if you want)

[NicolasHug]

Sure @adamjstewart , that sounds reasonable. A new issue sounds like the best way forward.

[NicolasHug]

I believe this was addressed in #7100 and thus this issue can be closed