Django：多对多循环参考

Question

我的模型有问题，因为我在多对多关系中有一个循环引用

这是我的Web应用程序的一部分，会话属于一个组（一个组可以有多个会话），每个会话都有一个以上的助手，但是助手只能是该会话组的成员

这是我的模型：

class GroupMember(models.Model):
    member = models.ForeignKey(Volunteer, null=True, blank=True)
    group = models.ForeignKey(Group)
    leader = models.BooleanField(default=False)
    created = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return '{}'.format(self.member)

class Session(models.Model):
    name = models.CharField(max_length=250)
    group = models.ForeignKey(Group)
    assistants = models.ManyToManyField(GroupMember,through=SessionAssistant)
    created = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return '{}'.format(self.name)

class SessionAssistant(models.Model):
    assistant = models.ForeignKey(GroupMember)
    session = models.ForeignKey(Session, null=True, blank=True, on_delete=models.CASCADE)
    assist = models.BooleanField(default=True)
    ability = models.IntegerField(null=True,
                              blank=True,
                              validators=[MaxValueValidator(5), MinValueValidator(1)])
    performance = models.IntegerField(null=True,
                                  blank=True,
                                  validators=[MaxValueValidator(5), MinValueValidator(1)])
    created = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return '{}'.format(self.assistant)

Answer 1

如果将assistants = models.ManyToManyField(GroupMember,through=SessionAssistant)更改为assistants = models.ManyToManyField(GroupMember,through='SessionAssistant')什么？