def assertPermutations(self, op, expected):
        fields = {
            User: User.username,
            UniqueModel: UniqueModel.name,
            OrderedModel: OrderedModel.title,
        }
        for key in itertools.permutations(fields.keys(), 2):
            if key in expected:
                left, right = key
                query = op(left.select(fields[left]).order_by(),
                           right.select(fields[right]).order_by())
                # Ensure the sorted tuples returned from the query are equal
                # to the sorted values we expected for this combination.
                self.assertValues(query, expected[key])
dataset/ETHPy150Open coleifer/peewee/playhouse/tests/test_compound_queries.py/TestCompoundSelectQueries.assertPermutations/original