sphinxjp.themes.tinkerdahlia
This package was deleted from PyPI around 2024-09-07. Installing fails with:
$ pip3 install sphinxjp.themes.tinkerdahlia
ERROR: Could not find a version that satisfies the requirement sphinxjp.themes.tinkerdahlia (from versions: none)
ERROR: No matching distribution found for sphinxjp.themes.tinkerdahlia

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/2024-09-06/ \
sphinxjp.themes.tinkerdahlia
Sign up for StableBuild to get an API key (it's free and takes <60 seconds!)