pytest-check-requirements
This package was deleted from PyPI around 2025-05-06. Installing fails with:
$ pip3 install pytest-check-requirements
ERROR: Could not find a version that satisfies the requirement pytest-check-requirements (from versions: none)
ERROR: No matching distribution found for pytest-check-requirements

Install through StableBuild
You can install this package from StableBuild's PyPI snapshots from before the version was deleted:
pip3 install \
-i https://YOUR_API_KEY.pypimirror.stablebuild.com/2025-05-05/ \
pytest-check-requirements
Sign up for StableBuild to get an API key (it's free and takes <60 seconds!)