docs: public Boolean notifyId(String notifyId){
          String url = Alipay.GATEWAY +
                  "&" + AlipayField.SERVICE.field() + "=" + Service.NOTIFY_VERIFY.value() +
                  "&" + AlipayField.PARTNER.field() + "=" + alipay.merchantId +
                  "&" + AlipayField.NOTIFY_ID.field() + "=" + notifyId;
          String resp = Http.get(url).request();
          return "true".equalsIgnoreCase(resp);
      }