如何使用GmailApp.sendEmail在电报机器人中发送照片，音频？

Question

function doPost(e){
  var data = JSON.parse(e.postData.contents);
  //Part 1
  if (data.message.text){
      var text = data.message.text;
      var id = data.message.chat.id;
      var name = data.message.chat.first_name ;
      var answer = "Hi " + name + ", thank you for your comment ";
      var answer2 = "Hi " + name + ", thank you for your comment " + "\n -----------\n " + text;
      sendText(id, answer);
      GmailApp.sendEmail(Session.getEffectiveUser().getEmail(), "Message send to Babak", answer2);
//Part 2
  } else if (data.message.photo) {
      var photo = data.message.photo;
      var text = data.message.text;
      var id = data.message.chat.id;
      var name = data.message.chat.first_name ;
      var answerToUser = "Hi " + name + ", thank you for your photo ";
      sendText(id, answerToUser);
      var answer2 = "Hi " + name + ", thank you for your comment " + "\n " + text; 
      GmailApp.sendEmail(Session.getEffectiveUser().getEmail(), answer2, photo );
  } else {
      var id = data.message.chat.id;
      var name = data.message.chat.first_name ;
      var answer = "Hi " + name + ",Only text message can be sent right now, photo, audio and video dev. is ongoing ";
      sendText(id, answer);
  }
}

第1部分工作正常，当我只发送短信，而不是第2部分。 问题：从电报机器人我发送索姆照片。 我从我的Gmail收到的结果是： 为什么我不从我的Gmail收到光子？

嗨巴巴克，谢谢你的评论未定义 [object Object]，[object Object]，[object Object]，[object Object]