pytorch

4beaf1cf - add typing runtime dependency for py2

add typing runtime dependency for py2 Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/28442 Test Plan: Imported from OSS Differential Revision: D18075498 fbshipit-source-id: 075f63b1ed2c83d9a64eb81224e0d67c6a63b22c