Hi, migration to casacore 3 in Debian introduced some failures. As you reported in upstream casacore project, namespace has changed a bit. I created this pull request that cherry-picks the relevant patch from upstream to fix the namespace issue in case upstream python-casacore does not release a new version soon.
I also fixed the few Build-Depends bits that will be needed anyway.
I tested those changes successfully on top of your latest master. Feel free to merge or not :)
F.