If a Python package does not come with either `format` or `pyproject` we consider it a setuptools build, that calls `setup.py` directly, which is deprecated. This change, as a first step, migrates a large chunk of these packages to set setuptools as their explicit format This is so we can unify the problem space for the next step of the migration.
Python 2 is Not Supported
Packages, applications, and services based on Python 2 are no longer supported and are being removed. If you require a Python 2 based package, you can include that package in your own local repository.
Some packages may continue to be maintained for internal use by nixpkgs, but they should not be used by new public packages.
For more details, see Issue #201859.