Let IDE(s) know public symbols

[akihironitta]

🚀 Feature (or Bug?)

I'm using Pylance on VSCode, and it doesn't autocomplete, for example, Accuracy even if I typed the following:

from torchmetrics import Ac

This is because imported symbols are considered private by default (by at least pylance (pyright) as documented here).

Motivation

For better coding experience (autocomplete + docstring reference) :]

Pitch

As stated in https://github.com/microsoft/pyright/blob/main/docs/typed-libraries.md#library-interface, we have the following options to explicitly make symbols public.

1. Add __all__ to __init__.py files.

# torchmetrics/__init__.py
from torchmetrics.classification import (
    Accuracy,
    ...
)
__all__ = [
    "Accuracy",
    ...
]

2. Use wildcard imports.

# torchmetrics/__init__.py
from torchmetrics.classification import *

# torchmetrics/classification/__init__.py
__all__ = [
    "Accuracy",
    ...
]

3. Use redundant symbol aliases.

# torchmetrics/__init__.py
from torchmetrics.classification import (
    Accuracy as Accuracy,
    ...
)

Additional context

microsoft/pylance-release#1032
microsoft/pyright#1877

[github-actions]

Hi! thanks for your contribution!, great first issue!

[SkafteNicki]

@akihironitta sounds good to me :]
I would prefer option 1 but have no strong opinions here.