Fix return types of Windows API functions in __init__.py (#39334)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/39327.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39334
Differential Revision: D21820898
Pulled By: malfet
fbshipit-source-id: ea771f8c44a152cee395ada70f8f129d4ad5283d
