def METHOD_NAME(self):
    """Return a dict with (key = score, value = list<user>) sorted in
    descending order"""
    # there may be ties!
    rev_tally = dict()
    for user, score in self.get_tally().items():
        if score not in rev_tally:
            rev_tally[score] = [user]
        else:
            rev_tally[score].append(user)
    # sort in descending order by score
    rev_tally = dict(
        sorted(rev_tally.items(), key=operator.itemgetter(0), reverse=True))
    return rev_tally