nothing provides if, nothing provides (%python-base without python36-base)

Hi, the package python-ciarocffi fails to build against pure Leap 15.3 & 15.4 with the above message. I guess there is some basic tool not on the latest level: setuptools, python-rpm-macros or other. Does anyone know which causes the issue? (in d:l:p, with additional repos, it builds....) Thanks Axel