def METHOD_NAME(self):
    """Ensures errors are detected and use provide good error messages."""
    with self.assertRaises(RuntimeError) as cm:
        mut.Dict[int]
    self.assertEqual(
        str(cm.exception),
        "Dict[] requires exactly 2 type parameter(s)")
    with self.assertRaises(RuntimeError) as cm:
        mut.List[int, float]
    self.assertEqual(
        str(cm.exception),
        "List[] requires exactly 1 type parameter(s)")
    with self.assertRaises(RuntimeError) as cm:
        mut.Optional[()]
    self.assertEqual(
        str(cm.exception),
        "Optional[] requires exactly 1 type parameter(s)")