Django 无法分配内容“U类型”；必须是一个"；“内容类型”；实例

我试图在我的博客上实现一个评论系统，但在尝试将

内容\u type

分配给评论附带的初始数据时出现了一个错误。下面是我的示例代码

python==3.8 django==3.1.1

#Comment app model
class Comment(models.Model):
    user            =   models.ForeignKey(User, on_delete=models.CASCADE)
    content_type    =   models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id       =   models.PositiveIntegerField()
    content_object  =   GenericForeignKey()
    parent          =   models.ForeignKey("self", null=True, blank=True, on_delete=models.CASCADE)
    content         =   RichTextField()

#Blog app model
class Song(models.Model):
    ...
    ...
    @property
    def get_content_type(self):
        content_type = ContentType.objects.get_for_model(self.__class__)
        return content_type

#Blog Views
class SongDetail(ModelFormMixin, DetailView):
    model       =   Song
    form_class  =   CommentsForm

    def get_initial(self):
        obj = self.get_object()
        return { 'content_type': obj.get_content_type, 'object_id': obj.object_id }

    def post(self, request, *args, **kwargs):
        if not request.user.is_authenticated:
            return redirect('music:obj.get_absolute_url()')
        
        form = self.get_form()
        if form.is_valid():
            return self.form_valid(form)
        else:
            return self.form_invalid(form)

---

此错误是否来自

表单\u valid（）

？您是否调试了用于创建

注释
对象的值？