mypy错误：Callable没有属性“ __get__”

Question

我有如下内容：

from typing import TypeVar, Callable, Generic, Type, Union, Optional

T = TypeVar("T")
V = TypeVar("V")

class DescClass(Generic[T, V]):
    """A descriptor."""
    def __init__(self, func: Callable[[T], V]) -> None:
        self.func = func

    def __get__(self, instance: Optional[T], owner: Type[T]) -> Callable[[], V]:
        return self.func.__get__(instance, owner)

class C:
    @DescClass
    def f(self): ...

... Mypy将为此返回错误：

test.py:12: error: "Callable[[T], Any]" has no attribute "__get__"

为func指定类型的规范方法是什么，以便Mypy理解它是描述符（and thus always has a __get__）？

更新：搜索Mypy帮助时，“描述符” has no hits有点幽默。