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

ruamel.yaml
0.18.4

This version was deleted from PyPI around 2023-11-03. Installing fails with:
$ pip3 install ruamel.yaml==0.18.4 ERROR: Could not find a version that satisfies the requirement ruamel.yaml==0.18.4
View other deleted versions of ruamel.yaml

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/2023-11-02/ \ ruamel.yaml==0.18.4
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Or, download files manually

And install manually via pip:
ruamel.yaml-0.18.4-py3-none-any.whl (113.4KB)
ruamel.yaml-0.18.4.tar.gz (138.8KB)