No, that's a different error. This introduces a new one. If you are going to try build this for leap I suggest you really take care about the errors. Thanks in advance

Someone once told me: I am maintainer, do as I say or else I don't accept. Oh the irony!

Anyway, if it won't build, I think you can make it unresolvable with the appropriate conditions. That would be a fair balance, I think.

I suggest doing this:

BuildRequires:  %{python_module devel >= 3.7}

to make this unresolvable for 15.4