Add Python string standard lib (#21059)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21059
ghimport-source-id: f813585cde1b275c134b19009a2f5c0b3d70fc6e
Reviewed By: jamesr66a
Differential Revision: D15830704
Pulled By: bwasti
fbshipit-source-id: e55a8c6bf910a163b9a5260235e315af9532b129
