def filter_site(self, queryset, value):
    value = value.strip()
    if (not value):
        return queryset
    return queryset.filter((Q(interface_a__device__rack__site__slug=value) | Q(interface_b__device__rack__site__slug=value)))
def filter_site(self, queryset, value):
    value = value.strip()
    if (not value):
        return queryset
    return queryset.filter((Q(interface_a__device__rack__site__slug=value) | Q(interface_b__device__rack__site__slug=value)))