问AdminDirectory.Members.insert返回“成员已存在”

EN

function AddNewMember()
{
    var LastEntryMail = "john.dow@gmail.com";
    var NewMember = 
        {
         email: LastEntryMail,
         role: 'MEMBER'
        };
    var MemberExist = false;
    var pageToken, page;
    var groupEmail = 'mygroup@bmydomain';
    var groupDomainName = 'mydomain';
    
    do 
    {
      page = AdminDirectory.Members.list(groupEmail,{
      domain: groupDomainName,
      orderBy: 'Email',
      maxResults: 200,
      pageToken: pageToken
      });
      var GroupMembers = page.members;
      for (var m in GroupMembers) 
      {
        var email = GroupMembers[m].email;
        if(email == LastEntryMail)     
        {
          MemberExist = true;
          break; //stop the for loop
        }
      }
      if(MemberExist == true)
      {
       break; //stop the do loop
      }
      else //new member email was not found in current page members list. go to next page
      {
       pageToken = page.nextPageToken;
      }
    } while (pageToken);
    
    if(MemberExist == false)
    {
      AdminDirectory.Members.insert(NewMember, groupEmail);
    }
  }