This package still uses the legacy eclass code paths. These paths are deprecated and pose a significant maintenance cost. Please update the package to use PEP517 build mode. For more information, please see the Python Guide, particularly; https://projects.gentoo.org/python/guide/migration.html#migrating-to-pep-517-builds
[Adding this comment en-masse, sorry for the noise, but it's important.)
1. Please take particular care to check file diffs before/after, possibly using `iwdevtools`. Keep a particular eye out for e.g. config files now missing from /etc and instead being in /usr/lib/python*/site-packages, etc.
2. Please make sure to do the migration in a new revision in ~arch, partly because of 1.