@attah, it’s not really a solution but another tangent. I’m trying to make some repairs to GitHub - lainwir3d/sailfish-rpn-calculator: A RPN calculator for Sailfish OS and came up with this hack.
with dependency directory in rpm/python_modules_src/{sympy,fastcache-1.0.2}
>> macros
%define __provides_exclude_from ^%{_datadir}/.*$
%define __requires_exclude ^libc|libdl|libm|libpthread|libpython3.7m|libpython3.4m|python|env|libutil.*$
# << macros
....
cd fastcache-1.0.2
python3 setup.py install --root=%{buildroot} --prefix=%{_datadir}/%{name}/
This works quite well. I’m just going to make the rpm directory a submodule and make the python modules submodules of that 