Allow optionals arguments from C++ (#19311)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19311
ghimport-source-id: 699f62eb2bbad53ff2045fb2e217eb1402f2cdc5
Reviewed By: eellison
Differential Revision: D14983059
Pulled By: driazati
fbshipit-source-id: 442f96d6bd2a8ce67807ccad2594b39aae489ca5
