如何更改dumpdata命令输出的fixture中权限字段的格式？

from django.core.serializers.base import Serializer

class CustomSerializer(Serializer):
    def serialize(self, queryset, **options):
        # 处理权限字段的格式
        for obj in queryset:
            # 获取权限字段的值
            permissions = obj.permissions.all()
            # 将权限字段转换为字符串格式
            permission_names = [permission.name for permission in permissions]
            # 更新对象的权限字段
            obj.permissions = permission_names

        # 调用父类的serialize方法进行序列化
        return super().serialize(queryset, **options)

SERIALIZATION_MODULES = {
    'custom': 'path.to.CustomSerializer',
}

python manage.py dumpdata --output=data.json --format=custom