this one felt a bit too easy -- I'm not sure how to change the problem to ... <summary>spoilers <details> ... require annotating [sic] `self` ```python from typing import * class Fn[R, **P]: def __init__(self, f: Callable[P, R]): self.f = f def transform_callable(self) -> Callable[Concatenate[object, P], R]: ... ``` </details> </summary>