django overload str method

The effect of modifying models is as follows

class EmailVerifyRecord(models.Model):
    code = models.CharField(max_length=20, verbose_name= u"验证码")
    email = models.EmailField(max_length=50, verbose_name=u"邮箱")
    send_type = models.CharField(choices=(("register",u"注册"),("forget",u"找回密码")), max_length=10 ,verbose_name=u"发送类型")
    send_Time = models.DateTimeField(default=datetime.now, verbose_name=u"添加时间")

    class Meta:
        verbose_name = u"邮箱验证码"
        verbose_name_plural = verbose_name
    #新增如下代码
    def __str__(self):
        return '{0}({1})'.format(self.code ,self.email)