如何在DRF序列化程序的GenericRelation字段中返回链接对象的计数？

from rest_framework import serializers

class LinkSerializer(serializers.Serializer):
    # 定义链接对象数量的字段
    link_count = serializers.SerializerMethodField()

    def get_link_count(self, obj):
        # 计算链接对象的数量
        return obj.links.count()

class ArticleSerializer(serializers.ModelSerializer):
    links = LinkSerializer(many=True)

    class Meta:
        model = Article
        fields = ('id', 'title', 'content', 'links')