query.python

    def parse_intersection(self, filters):
        first_filter = filters[0]['gene']
        second_filter = filters[1]['gene']
        print('filters', first_filter, second_filter)
        # Doesn't work - seems to ignore one of the Qs
        #qs = Rule.objects.filter(Q(gene_traits__pk=first_filter) and Q(gene_traits__pk=second_filter))

        # Doesn't work - seems to ignore one of the filters.  This should be the same as the query below.
        #qs = Rule.objects.filter(gene_traits__pk=first_filter)
        #qs.filter(gene_traits__pk=second_filter)

        # Works
        qs = Rule.objects.filter(gene_traits__pk=first_filter).filter(gene_traits__pk=second_filter)
        return qs