> It shouldn't be hard to do the equivalent of:

Right, that's not hard at all. But is it what we *want* to do? Why do you single out `int` for special treatment, but not `Fraction` or `Decimal`? How should the implementation handle Fraction objects, and why? How should the implementation handle a Fraction-like object implemented by a user? Why only objects of exact type `int`, but not instances of subclasses? Your suggestion replaces a straightforward mental model (math.isnan converts its input to float, then operates on it, just like almost all other math module functions) with something more complicated.

-1 from me.