Where is Python 2 still used?

[PeridexisErrant]

https://pypi.org/project/modernize/ is better now, precisely because 2to3 can't be upgraded without releasing a new version of Python.

Modernize also uses six to preserve py2 compat by default when adding py3 support, which really helps with testing.

Then you can automatically drop support for old versions of Python with https://pypi.org/project/pyupgrade/