问小程序调用腾讯云人脸识别人员搜索按库返回接口显示is not a constructor怎么解决？

{"errorCode":1,"errorMessage":"user code exception caught","stackTrace":"models.SearchPersonsReturnsByGroupRequest is not a constructor\nTypeError: models.SearchPersonsReturnsByGroupRequest is not a constructor\n    at synSearchPersonsReturnsByGroup (/var/user/index.js:18:13)\n    at EventHandler.exports.main [as realHandler] (/var/user/index.js:40:17)\n    at \u003canonymous\u003e\n    at process._tickCallback (internal/process/next_tick.js:188:7)"}

const cloud = require('wx-server-sdk') //小程序云开发SDK
const tencentcloud = require("tencentcloud-sdk-nodejs"); //腾讯云API 3.0 SDK
cloud.init() //云开发初始化
var synSearchPersonsReturnsByGroup = function (groupid, url) { //人脸识别API
 const IaiClient = tencentcloud.iai.v20180301.Client; //API版本
 const models = tencentcloud.iai.v20180301.Models; //API版本
 const Credential = tencentcloud.common.Credential;
 const ClientProfile = tencentcloud.common.ClientProfile;
 const HttpProfile = tencentcloud.common.HttpProfile;
 let cred = new Credential();  //这里填入你的SecretID和Secretkey,在腾讯云账号信息可以找到
 let httpProfile = new HttpProfile();
  httpProfile.endpoint = "iai.tencentcloudapi.com"; //腾讯云人脸识别API接口
 let clientProfile = new ClientProfile();
  clientProfile.httpProfile = httpProfile;
 let client = new IaiClient(cred, "", clientProfile); //调用就近地域
 let req = new models.SearchPersonsReturnsByGroupRequest();
 let params = '{"GroupIds.0":"' + groupid + '", "Url": "' + url + '", "SignatureMethod": "TC3-HMAC-SHA256"}' //拼接参数
  req.from_json_string(params);
 return new Promise(function (resolve, reject) { //构造异步函数.
    client.SearchPersonsReturnsByGroup(req, function (errMsg, response) {
 if (errMsg) {
        reject(errMsg)
      } else {
        resolve(response);
      }
    })
  })
}
exports.main = async (event, context) => {
 const data = event
 const fileList = [data.fileID] //读取来自客户端的fileID
 const result = await cloud.getTempFileURL({
    fileList, //向云存储发起读取文件临时地址请求
  })
 const url = result.fileList[0].tempFileURL
  datas = await synSearchPersonsReturnsByGroup(data.groupid, url) //调用异步函数，向腾讯云API发起请求
 return datas
}