我对Django和编程非常陌生。我在尝试运行时看到以下错误 没有要重定向到的URL。在模型上提供一个URL或定义一个get_absolute_url方法。

下面是我的模型定义

class Group(models.Model):
    author = models.ForeignKey('auth.User',on_delete=models.CASCADE)
    title = models.CharField(max_length=200)
    group_description = models.TextField()
    created_date = models.DateTimeField(
        default=timezone.now)
    published_date = models.DateTimeField(
        blank=True,null=True)

    def publish(self):
        self.published_date = timezone.now()
        self.save()

    def __str__(self):
        return self.title

    def get_absolute_url(self):
        self.save()
        return reverse('group-detail',kwargs={'pk': self.pk})


class GroupPost1(models.Model):
    title = models.CharField(max_length=100)
    content = models.TextField()
    date_posted = models.DateTimeField(default=timezone.now)
    author = models.ForeignKey(User,on_delete=models.CASCADE)
    group1 = models.ForeignKey('Group',on_delete=models.CASCADE,null=True)

    def __str__(self):
        return self.title

    def get_absolute_url(self):
        self.save()
        return reverse('group-post-detail',kwargs={'group_pk': self.group1.id,'group_post_pk': self.pk})

我的模型中有get_absolute_url def。为什么会看到此错误？任何帮助将不胜感激

谢谢