Enable typechecking for utils.py (#112971)
Summary:
X-link: https://github.com/pytorch/pytorch/pull/112971
Approved by: https://github.com/lezcano, https://github.com/jansel
ghstack dependencies: #112130, #112970
Reviewed By: PaliC
Differential Revision: D51140165
Pulled By: int3
fbshipit-source-id: a0613683717d9e697ba3b5d311f7d6908c46a928
