Javascript 谷歌应用程序脚本UrlFetchApp异常

我正在使用谷歌文档和谷歌应用脚本创建自定义时间表。其中一个要求是在用户提交时间表时将时间表保存为PDF格式。以下是我目前拥有的：

function createPdf(){

  var ss = SpreadsheetApp.getActiveSpreadsheet();

  var oauthConfig = UrlFetchApp.addOAuthService("google");
  oauthConfig.setAccessTokenUrl("https://www.google.com/accounts/OAuthGetAccessToken");
  oauthConfig.setRequestTokenUrl("https://www.google.com/accounts/OAuthGetRequestToken?scope=https://spreadsheets.google.com/feeds/");
  oauthConfig.setAuthorizationUrl("https://www.google.com/accounts/OAuthAuthorizeToken");
  oauthConfig.setConsumerKey("anonymous");
  oauthConfig.setConsumerSecret("anonymous");

  var url =  "https://spreadsheets.google.com/feeds/download/spreadsheets/Export?key="
      + ss.getId() +  "&gid=0&portrait=true" +"&exportFormat=pdf";

  var requestData = {
    "oAuthServiceName": "google",
    "oAuthUseToken": "always"
  };

  var result = UrlFetchApp.fetch(url, requestData);
  var content = result.getBlob();
  var file = DocsList.createFile(content);

  return file;

}

调试脚本时，出现以下错误：

序列化继续时出现意外异常

---

任何帮助都将不胜感激。

经过进一步挖掘，我找到了以下解决方案：

function createPdf(){

  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var pdf = ss.getAs("application/pdf");
  var file = DocsList.createFile(pdf);
  file.rename("Test");

  return file;

}