Although TypedDicts are not meant for runtime checking, there are times where I want to implement a type narrower to a typeddict. To implement a generic type narrower for any dict, I'd like to know that the type to be narrowed to is a typed dict. I tried using is_subhint, but that essentially raised an error complaining that TypedDict cannot be used with subclass checks. I think when checking for subtypes for TypedDicts, one must explicitly check that the annotations are subhints of each other. Is it possible/worth it to implement this?