> FWIW, the entire point of us having recently added as_integer_ratio() methods to so many concrete classes is to avoid the need for helper functions in favor of a simple try/except around a single call.

But what about PEP 3141? The fractions.Fraction constructor accepts numbers.Rational instances, which do not necessarily have an as_integer_ratio() method. We can't just drop support for that (*). So in practice you do need to check both as_integer_ratio() and the PEP 3141 numerator/denominator properties. It seems useful to have a helper function for this.

(*) Unless you want to deprecate PEP 3141. This may be less crazy than it sounds, especially given Guido van Rossum's reaction on https://discuss.python.org/t/pep-3141-ratio-instead-of-numerator-denominator/2037/25?u=jdemeyer