You're looking at StableBuild's Deleted PyPI mirror - where we index all deleted packages from the Python package registry.

pen-stack
4.0.0

This version was deleted from PyPI around 2026-07-21. Installing fails with:
$ pip3 install pen-stack==4.0.0 ERROR: Could not find a version that satisfies the requirement pen-stack==4.0.0
View other deleted versions of pen-stack

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/2026-07-20/ \ pen-stack==4.0.0
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Or, download files manually

And install manually via pip:
pen_stack-4.0.0-py3-none-any.whl (279.3KB)
pen_stack-4.0.0.tar.gz (1.5MB)