onnx.symbolic_helper.parse_args: document and clean up (#56956) (#57598)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57598
Add a doc string to explain what it does and how to use it.
Remove hack around a bug in Python 2's functools.wrap().
Python 2 is no longer supported.
Test Plan: Imported from OSS
Reviewed By: malfet
Differential Revision: D28393519
Pulled By: SplitInfinity
fbshipit-source-id: aae8c5e7b49e2ad2d24a0e86f8ba47f1cd080e46
Co-authored-by: Gary Miguel <garymiguel@microsoft.com>
