pytorch

16c72a5a - [pytorch] continue to rewrite gen_python_functions.py with typed models (#46978)

[pytorch] continue to rewrite gen_python_functions.py with typed models (#46978) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/46978 Refactored and added type annotations to the most part of the file. Some top-level codegen functions are called by other codegen scripts. Will migrate them in subsequent PRs. Test Plan: Imported from OSS Reviewed By: ezyang Differential Revision: D24589210 Pulled By: ljk53 fbshipit-source-id: e0c7e5b3672b41983f321400c2e2330d1462e76e