You don't need Requires: python-base (as explained elsewhere), but you need BuildRequires: python-rpm-macros, without which you have all those failed builds on other platforms than Tumbleweed.

Ah, I guess I should have included BuildRequires: python-rpm-macros here (surprised it worked without it...), but the failed builds on other platforms happens by using %python_subpackages in the openSUSE python-rpm-macros .

See https://build.opensuse.org/package/show/home:jayvdb:moban/python-crayons for an example of an unmodified openSUSE package which fails. I did have a concoction of macro overrides which fixed this, but they have been broken by the latest openSUSE python-rpm-macros.