django m2m\u已更改不工作

我有简单的代码,bug不起作用! 向未调用的内容添加标记后 tag_update_count_use 哦!

型号。py公司

class Tag(models.Model):
    count_use = models.PositiveIntegerField(_('count use'), default=0)

    def update_count_use(self, delta):
        self.count_use += delta
        self.save(update_fields=['count_use'])

class Content(models.Model):
    tags = models.ManyToManyField('Tag', blank=True, verbose_name=_('tags'))

信号。py公司

from django.db.models.signals import m2m_changed
from django.dispatch import receiver

@receiver(m2m_changed, sender=Content.tags)
def tag_update_count_use(sender, **kwargs):
    print(kwargs)
    return kwargs

__init\uuuu。py公司

default_app_config = 'content.apps.ContentConfig'

应用程序。py公司

class ContentConfig(AppConfig):
    name = 'content'
    verbose_name = _('content')

    def ready(self):
        import content.signals

根据 https://docs.djangoproject.com/en/dev/ref/signals/#m2m-changed 我将代码更改为:

@receiver(m2m_changed, sender=Content.tags.though)

但我收到以下错误:

AttributeError: 'ManyToManyDescriptor' object has no attribute 'though'