[Python-ideas] Instance method to test equivalence between set and iterable

Currently, the `issubset` and `issuperset` methods of set objects accept arbitrary iterables as arguments. An iterable that is both a subset and superset is, in a sense, "equal" to the set. It would be inappropriate for `==` to return `True` for such a comparison, however, since that would break the `Hashable` contract. Should sets have an additional method, something like `like(other)`, `issimilar(other)`, or `isequivalent(other)`, that returns `True` for any iterable that contains the all of the items in the set and no items that are not in the set? It would therefore be true in the same cases where `<set> = set(other)` or `<set>.issubset(other) and <set>.issuperset(other)` is true.