[Typing-sig] Re: Any way to express that a dict is expected to have a key(s) but don't care about other keys?

For what it's worth, at runtime it will work fine to do this with: ``` def transpose(p: P) -> P: return { **p, "x": p['y'], "y": p['x'], } ``` MyPy complains about this but Pyre and Pyright both accept it.