如何使用类型注释来指示未知长度的Tuple类型参数是返回的映射的关键？

Question

Say I've got a function like this:

def a_function(data: Tuple[Tuple[str, ...], ...]) -> Mapping[Tuple[str, ...], int]:
    pass

Is there a way to indicate via type annotations that the Tuple[str, ...] is going to be the same Tuple[str, ...] that is passed in via the data parameter?

In other words, the tuple being passed in will contain a homogenous list of homogenous tuples that all might look like ('fred', 'smith'), ('ananya', 'cooper') and the returned dict will look like {('fred', 'smith'): 7, ('ananya', 'cooper'): 13} .

Answer 1

I don't know if that's what would satisfy you, but you could do something like this:

SomeType = TypeVar('SomeType', Tuple[str, ...])


def a_function(data: Tuple[SomeType, ...]) -> Mapping[SomeType, int]:
    pass