If a type scheme is instantiated, should the type variables in the
class body be substituted?  This is an example (typed by hand on
a locked down Windows machine, may contain errors):


alpha = TypeVar('alpha')
beta = TypeVar('beta')

class ABTuple(Generic[alpha, beta]):
    def __init__(self, a : alpha, b : beta):
        self.value = (a, b)

get_type_hints(ABTuple.__init__)
 ==> {'b': ~beta, 'a': ~alpha}


IntIntTuple = ABTuple[int, int]

IntIntTuple
 ==> __main__.ABTuple[int, int]

get_type_hints(IntIntTuple.__init__)
{'b': ~beta, 'a': ~alpha}
      ^^^^^^      ^^^^^^


Since the type has been specialized, these should ideally be 'int'.