docs: def get_subscribe_authorize_url(self, scene, template_id, redirect_url, reserved=None):
          """
          构造请求用户授权的url
          详情请参阅：
          https://mp.weixin.qq.com/wiki?id=mp1500374289_66bvB
  
          :param scene: 订阅场景值，开发者可以填0-10000的整形值，用来标识订阅场景值
          :type scene: int
          :param template_id: 订阅消息模板ID，登录公众平台后台，在接口权限列表处可查看订阅模板ID
          :param redirect_url: 授权后重定向的回调地址
          :param reserved: 用于保持请求和回调的状态，授权请后原样带回给第三方。该参数可用于防止csrf攻击。若不指定则随机生成。
          """
          if reserved is None:
              reserved = random_string()
          base_url = 'https://mp.weixin.qq.com/mp/subscribemsg'
          params = [
              ('action', 'get_confirm'),
              ('appid', self.appid),
              ('scene', scene),
              ('template_id', template_id),
              ('redirect_url', redirect_url),
              ('reserved', reserved),
          ]
          encoded_params = six.moves.urllib.parse.urlencode(params)
          url = '{base}?{params}#wechat_redirect'.format(base=base_url, params=encoded_params)
          return url