"This change doesn't catch any of the bugs anyone was going to hit (no-one is passing a callable to this parameter), and it doesn't catch any of the bugs someone might actually hit (getting the tuple elements in the wrong order, for example). At this point the type signature is worse than useless."
> At this point, you may want to just stop caring about the exact type.
> Part of the point of gradual typing is that you can short-cut a lot of
> this. And quite frankly, this isn't really helping anything. Just skip
> it and say that it's Union[Mapping, Iterable, None].