Actually, unless we don't modify the dictionary at all, simply calling `get` wouldn't change much, as the logic in this function would then move to `get`.  The main thing getting in the way of simplifying all of this is that we only want to call `d.default()` when the value is not in the dictionary.

Abstractly, what would be useful is a function which, e.g, returns a `token` that indicates whether or not a key is in the dictionary, as well as indicating (to the dictionary) the location of the `key` if it exists, or where it would go if it doesn't exist.  Making such a function public would allow hash values to be returned to the caller.