Python 如何过滤列表属性'；s的长度是“0”？

我有一个

ListAPIView

，这是访问url

localhost:8000/api/physicalserver\u任务/列表的结果：

{
    "count": 1,
    "next": null,
    "previous": null,
    "results": [
        {
            "id": 16,
            "physicalservers": [],
            ...

代码如下：

class PhysicalServerTaskListForHomeWorkPanelAPIView(ListAPIView):
    serializer_class = PhysicalServerTaskListForHomeWorkPanelSerializer
    permission_classes = [IsAdminUser]
    pagination_class = CommonPagination

    def get_queryset(self):
        filters = {'{}__contains'.format(key): value
               for key, value in query_params.items()}
        return PhysicalServerTask.objects.filter(**filters)

class PhysicalServerTaskListForHomeWorkPanelSerializer(ModelSerializer):

    physicalservers = PhysicalServerTaskSerializer(many=True, read_only=True)

    physicalserver_count = serializers.IntegerField(write_only=True, allow_null=True)

    class Meta:
        model = PhysicalServerTask
        fields = "__all__"
        depth = 1

我有一个要求，那就是过滤
physicalservers
的长度是
0

你知道，如果我们只是过滤
id
，我们可以使用

localhost:8000/api/physicalserver_task/list/?id=16

但是如果我想过滤
physicalservers
的计数为
0
，该怎么办


编辑-1

我的Serializer代码如下：

class PhysicalServerTaskListForHomeWorkPanelAPIView(ListAPIView):
    serializer_class = PhysicalServerTaskListForHomeWorkPanelSerializer
    permission_classes = [IsAdminUser]
    pagination_class = CommonPagination

    def get_queryset(self):
        filters = {'{}__contains'.format(key): value
               for key, value in query_params.items()}
        return PhysicalServerTask.objects.filter(**filters)

class PhysicalServerTaskListForHomeWorkPanelSerializer(ModelSerializer):

    physicalservers = PhysicalServerTaskSerializer(many=True, read_only=True)

    physicalserver_count = serializers.IntegerField(write_only=True, allow_null=True)

    class Meta:
        model = PhysicalServerTask
        fields = "__all__"
        depth = 1

您可以使用
PhilicalServers\uuu isnull
查找：

def get_queryset(self):
    filters = {'{}__contains'.format(key): value
           for key, value in query_params.items()}
    if query_params.get('serverscount') == 0:
        filters.update({'phisicalservers__isnull': True})
    return PhysicalServerTask.objects.filter(**filters)

在Python中，None是否为null？@qg_java_17137在Python中，None类似于null。但是在这个查询中，
\u isnull
查找也匹配空的关系集。