Combine django querysets

chain_django_qs.py

    def chain_qs(*querysets):
        class CombinedQuerySet:
            def __init__(self, *querysets):
                self.qs_list = querysets

            def __next__(self):
                return chain(self.qs_list)

            def __iter__(self):
                return self

            next = __next__

            def __len__(self):
                return sum(len(q) for q in self.qs_list)

        return CombinedQuerySet(querysets)