There is an updated pull request by ndowens against master on the void-packages repository

https://github.com/ndowens/void-packages python-altgraph
https://github.com/void-linux/void-packages/pull/26467

python3-altgraph: update to 0.17
Add check target

A patch file from https://github.com/void-linux/void-packages/pull/26467.patch is attached