Method _not_support_combined_queries

django/db/models/query.py:2312–2317

(self, operation_name)

            )

    def _not_support_combined_queries(self, operation_name):
        if self.query.combinator:
            raise NotSupportedError(
                "Calling QuerySet.%s() after %s() is not supported."
                % (operation_name, self.query.combinator)
            )

    def _check_operator_queryset(self, other, operator_):
        if self.query.combinator or other.query.combinator: