Sure, but at that point you've just reimplemented python in macros ;)

The other thing to note is that

    sorted([(k.weight, k.name) for k in somelist], reverse=True)

is essentially already typechecked:

    def biggest_ks(ks: K):
        return sorted([(k.weight, k.name) for k in ks], reverse=True)

The above code now has all the same type guarantees as your c++, actually maybe more since the macros you use are going to be...uhhh, mysterious.