Handle autocomplete in IDE

[Wauplin]

At the moment, when importing from huggingface_hub root module, autocomplete in IDE doesn't work (both method name + arguments/docstring). This is due to the lazy-loading have in __init__.py. From a UX perspective, It would be good to make the autocomplete work properly.

from huggingface_hub import upload_file # <- lazy-loading but no autocomplete
from huggingface_hub.hf_api import upload_file # <- autocomplete but no lazy-loading

Tested in both vscode (+Python/Pylance extensions) and PyCharm.

Maybe a if TYPE_CHECKING with imports behind is enough to solve that.

(cc @LysandreJik who reported it to me)

Note: autocomplete works in transformers.

[LysandreJik]

Adding a quick note that autocomplete + lazy loading can work in parallel as we have seen in transformers. Also cc @sgugger who has worked on that in transformers.

[sgugger]

I do believe a TYPE_CHECKING block would be enough to solve that, we have one in Transformers for this purpose and I think this is the only big difference between the two kinds of lazy loading (we have a different implementation not relying on Python 3.7 in Transformers but that does the same thing as huggingface_hub as far as I could tell).

It becomes annoying to have to make sure the two blocks are synchronized, which is why I built a quality script in Transformers to check the two parts of an init contain the same object.