stdlib/importlib/machinery declares loaders to be instantiated, they should be classes

[Spindel]

class FileFinder(importlib.abc.PathEntryFinder):
    path: str
    def __init__(self, path: str, *loader_details: tuple[importlib.abc.Loader, list[str]]) -> None: ...
    @classmethod
    def path_hook(
        cls, *loader_details: tuple[importlib.abc.Loader, list[str]]
    ) -> Callable[[str], importlib.abc.PathEntryFinder]: ...

where both cases of loader_details should be Tuple[Type[importlib.abc.Loader, list[str]], as the code itself will create a new instance of the loader passed in.

compared with python 3.10