temp fix for flake8 error (#18788)
Summary:
Fix lint error
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18788
Reviewed By: houseroad
Differential Revision: D14741840
Pulled By: mingzhe09088
fbshipit-source-id: 1fa630e3c6e606e3d78fe8293e5b0e7ea1b78da3
