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

pyfast
3.1.1.post0

This version was deleted from PyPI around 2024-01-24. Installing fails with:
$ pip3 install pyfast==3.1.1.post0 ERROR: Could not find a version that satisfies the requirement pyfast==3.1.1.post0
View other deleted versions of pyfast

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/2024-01-23/ \ pyfast==3.1.1.post0
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Or, download files manually

And install manually via pip:
pyFAST-3.1.1.post0-cp36-cp36m-manylinux1_x86_64.whl (84.1MB)
pyFAST-3.1.1.post0-cp37-cp37m-manylinux1_x86_64.whl (84.1MB)
pyFAST-3.1.1.post0-cp38-cp38-manylinux1_x86_64.whl (84.2MB)