def filter_site(self, queryset, value):
    value = value.strip()
    if (not value):
        return queryset
    return queryset.filter(cs_port__device__rack__site__slug=value)
def filter_site(self, queryset, value):
    value = value.strip()
    if (not value):
        return queryset
    return queryset.filter(cs_port__device__rack__site__slug=value)