BTW, *all* of the Python applications I really care about make a point of specifying a range of versions they work with (or bundle a particular version).
Yes, well that was my point exactly.
If opinion is against commas, then we can take them out.
That would give us something like:
Requires-python: 2.5 2.6 2.7 3
That would specify a bundle of versions.
Processing that only requires the string split() function.
If we were to adds Lens suggestion of the range indicator that would simplify things even more.
Requires-python: 2.5:2.7 3
That would specify everything between 2.5 and 2.7 and then everything in the 3 series.
This would make it very simple.