我将以下 lambda 函数设置为 Cognito 中的确认后触发器。有人知道为什么我会收到“无效的 lambda 函数输出：无效的 JSON”？

我从 CloudWatch 中的“console.log("params",params)”获取日志，但没有从“console.log("inside adminAddUserToGroup",params)”获取日志。

const AWS = require('aws-sdk');
AWS.config.region = 'us-east-1';
const lambda = new AWS.Lambda();

type TriggerEvent = {
  version: string,region: string,userPoolId: string,username: string,callerContext: {
    awsSdkVersion: string,clientId: string
  },triggerSource: string,request: {
    userAttributes: {
        sub: string,'cognito:email_alias': string,'cognito:user_status': string,birthdate: string,email_verified: string,gender: string,preferred_username: string,email: string
    }
  },response: {}
}

exports.handler = async (event:TriggerEvent,context: any,callback: any) => {
    var cognitoIdentityServiceProvider = new AWS.CognitoIdentityServiceProvider({ apiVersion: '2016-04-18' });

    console.log("event",event);
    var params = {
        GroupName: 'customers',UserPoolId: event.userPoolId,username: event.username
    };
    console.log("params",params)
    try {
        cognitoIdentityServiceProvider.adminAddUserToGroup(params,function(err: any,data: any) {
            console.log("inside adminAddUserToGroup",params)
            if (err) {
                console.log(err,err.Stack);
                context.done(err);
            }
            context.done();
        });
    } catch (err) {
        console.log("Add user to group catch err",err);
        context.fail("Add user to group catch err");
    }

}

谢谢。