Typing decorators which enrich a class

Hi

I would like to type a decorator which takes as input a class and returns the same class with added attributes, i.e., a subclass.
Example:

import typing

_T = typing.TypeVar("_T")


def config(*, /, prefix: str) -> typing.Callable[[typing.Type[_T], ???]:
    def wrap(cls: typing.Type[_T]) -> ???:
        class Subclass(cls):  # or could do cls.prefix = prefix instead of subclassing
            prefix: str = prefix

        return Subclass

    return wrap


@config(prefix="test")
class A:
    ...


print(A.prefix)

Been searching for an answer and experimenting for a few days now and can't find anything concrete. Any help would be much appreciated

Thank you

No files, tests, or entry points are named. Start by reviewing the current guidance for typing class decorators and the behavior of type checkers for the shown config and wrap signatures; done should mean there is a documented, accepted way to preserve the input class type while exposing the added prefix attribute.