Generic ParamSpec in subclass definitions

Given some base class that is generic over a param-spec, I'd like to be able to define the param-spec using a subclass method implementation. Something like:

T = TypeVar("T")
P = ParamSpec("P")

class Base(Generic[P, T]):
    func: Callable[P, T]
    # for instance
    def wrapper(self, *args: P.args, **kwargs: P.kwargs) -> Tuple[T]:
        return (self.func(*args, **kwargs), )
        
class Subclass(Base):
    def func(self, x: int, *, y: str) -> bytes: ...

That is, the base class is generic over some function definition, and the subclass implement that function as a method. I'm not sure how common this pattern is, but I see it a fair amount when the class gets more complicated and you can't just use a decorator (e.g. torch.nn.Module.forward is a big example of this). Is there some other way of specifying "infer the parameters from this method implementation"? Is this something that would require an update to the specification, is it "just" a feature request to the method implementation "like" an assignment statement?

No file, test, or implementation entry point is named. Start by reviewing the issue's ParamSpec, Generic, and subclass-method example alongside the Python typing specification; determine whether the requested inference is supported or requires a specification change. Done means the behavior and its implementation scope are explicitly decided.