from PEP8
(https://peps.python.org/pep-0008/#programming-recommendations):
> Comparisons to singletons like None should always be done with is or
is not, never the equality operators.
Co-authored-by: Eisuke Kawashima <e-kwsm@users.noreply.github.com>
This is an ongoing series of commits that are reformatting our Python
code. Reformatting is done with `black` (23.1.0).
If you end up having problems merging this commit because you have made
changes to a python file, the best way to handle that is to run `git
checkout --ours <yourfile>` and then reformat it with black.
RFC: https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style
Differential revision: https://reviews.llvm.org/D151460
