def test_load_get_known_extids() -> None:
    """Checks PackageLoader.load() fetches known extids efficiently"""
    storage = Mock(wraps=get_storage("memory"))

    class StubPackageInfo(BasePackageInfo):
        pass

    def MyPackageLoader(PackageLoader):
        def get_versions(self):
            return ["v1.0", "v2.0", "v3.0"]

        def get_package_info(self, version):
            p_info = StubPackageInfo("http://example.org/")
            extid_type = "extid-type1" if version in ("v1.0", "v2.0") else "extid-type2"
            # Versions 1.0 and 2.0 have an extid of a given type, v3.0 has an extid
            # of a different type
            patch(
                p_info,
                "extid",
                autospec=True,
                return_value=(extid_type, f"extid-of-{version}".encode()),
            )
            return p_info

    loader = PackageLoader(storage, "http://example.org")    # passes
    loader = MyPackageLoader(storage, "http://example.org")  # TypeError: MyPackageLoader() takes 1 positional argument but 2 were given