Return (key, value) item pair at index.

        Unlike ``popitem``, the sorted dictionary is not modified. Index
        defaults to -1, the last/greatest key in the dictionary. Specify
        ``index=0`` to lookup the first/least key in the dictiony.

        If index is out of range, raise IndexError.

def peekitem(self, index=-1):
        """Return (key, value) item pair at index.

        Unlike ``popitem``, the sorted dictionary is not modified. Index
        defaults to -1, the last/greatest key in the dictionary. Specify
        ``index=0`` to lookup the first/least key in the dictiony.

        If index is out of range, raise IndexError.

        """
        key = self._list[index]
        return key, self[key]