Better type Module.apply signature - PR discussion

[Daraan]

Following up on #2086 and this recent SO question How to type hint flax.linen.Module.apply's output correctly?.

I would like to add a PR based on my answer and add two typing.overload signatures that make it more clear when to expect a tuple return value - following the contribution guidelines I am opening this issue first.

Based on #2086, the docstring and

flax/flax/core/scope.py

Lines 1080 to 1083 in 893a660

	if mutable is not False:
	return y, root.mutable_variables()
	else:
	return y

I am certain that only mutable=False never returns a tuple, otherwise it will always be a tuple.