django - Django - 创建用户异常

Question

我正在尝试在 Django 项目中创建一个新用户。models.py 中的方法create_user()在以下行中引发异常：

user.save(using=self._db)

这是方法：

def create_user(self, username, email, password=None):
    """
    Creates and saves a User with the given username, e-mail and password.
    """
    now = datetime.datetime.now()

    # Normalize the address by lowercasing the domain part of the email
    # address.
    try:
        email_name, domain_part = email.strip().split('@', 1)
    except ValueError:
        pass
    else:
        email = '@'.join([email_name, domain_part.lower()])

    user = self.model(username=username, email=email, is_staff=False,
                     is_active=True, is_superuser=False, last_login=now,
                     date_joined=now)

    user.set_password(password)
    user.save(using=self._db)
    return user

有什么建议么？