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

testbrain
1.0.0.dev4

This version was deleted from PyPI around 2023-10-06. Installing fails with:
$ pip3 install testbrain==1.0.0.dev4 ERROR: Could not find a version that satisfies the requirement testbrain==1.0.0.dev4
View other deleted versions of testbrain

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/2023-10-05/ \ testbrain==1.0.0.dev4
Sign up for StableBuild to get an API key (it's free and takes <60 seconds!)

Or, download files manually

And install manually via pip:
testbrain-1.0.0.dev4-py2-none-any.whl (31.5KB)
testbrain-1.0.0.dev4.tar.gz (14.0KB)