pytorch

f1ce64a5 - Starter Task 1 (#64927)

Starter Task 1 (#64927) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/64927 Mypy error corrections Test Plan: Corrected mypy errors to make code less prone to bugs by modifying types or adding lines that avoid special undesired cases e.g. asserting a variable to not None. Reviewed By: wushirong Differential Revision: D30901654 fbshipit-source-id: daae8692603b8b38203a98f673c455749c2fb855