问django 'User‘object没有属性'user’

EN

class User(AbstractDateTime, AbstractBaseUser, PermissionsMixin, models.Model):

    email = models.EmailField(max_length=255, unique=True,blank=False,default='')
    first_name = models.CharField(max_length=255, blank=False,default='')
    last_name = models.CharField(max_length=255, blank=False,default='')
    merchant_id = models.CharField(max_length=255, blank=True,default='')
    customer_id = models.CharField(max_length=255, blank=True,default='')
    phone_number = models.CharField(max_length=255,blank=False,default='')
    zip_code = models.CharField(max_length=10,blank=False,default='')
    photo = models.FileField(upload_to='images/users', default=None, blank=True, null=True)
    STATUS_TYPES = (('admin', 'admin'),('client', 'client'))
    role = models.CharField(max_length=10,choices=STATUS_TYPES,default='client')
    reset_key = models.CharField(max_length=255, blank=True,default='')
    credits = models.DecimalField(max_digits=5, decimal_places=2,default=0)
    is_staff = models.BooleanField(default=0)
    is_active = models.BooleanField(default=1)
    objects = AuthUserManager()
    USERNAME_FIELD = 'email'


    def last_seen(self):
        return cache.get('seen_%s' % self.user.email)

    def online(self):
        if self.last_seen():
            now = datetime.datetime.now()
            if now > self.last_seen() + datetime.timedelta(
                         seconds=settings.USER_ONLINE_TIMEOUT):
                return False
            else:
                return True
        else:
            return False

    def get_full_name(self):
        full_name = '%s %s' % (self.first_name, self.last_name)
        return full_name.strip()

    def get_short_name(self):
        return self.first_name

    def __unicode__(self):
        return unicode(self.email) or 'not found'



    class Meta:
        ordering = ["id"]
        db_table = "user"
        get_latest_by = "created"

users = User.objects.filter()
for user in users:
    user.online()