Django DRF和泛型关系:如何从接口响应中获取content_object字段？

from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
from django.contrib.contenttypes.models import ContentType
from django.db import models
from rest_framework import serializers

class Comment(models.Model):
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')
    text = models.TextField()

class CommentSerializer(serializers.ModelSerializer):
    class Meta:
        model = Comment
        fields = ['id', 'content_type', 'object_id', 'content_object', 'text']

class CommentSerializer(serializers.ModelSerializer):
    content_object = serializers.SerializerMethodField()

    def get_content_object(self, obj):
        return str(obj.content_object)

    class Meta:
        model = Comment
        fields = ['id', 'content_type', 'object_id', 'content_object', 'text']