function getLatestMailAttachment(thread_search_str, usefirst)
  {
    if(typeof(usefirst) == 'undefined')
      usefirst = true;

    // search for all threads matching our criteria
    var threads = GmailApp.search(thread_search_str, 0, 1);

    // loop through all found threads
    for(var i = 0; i < threads.length; i++)
    {
      // ok so gonna assume here that the first thread is the most recent
      var thread = threads[i];

      // do we have none or too many messages?
      var messages = thread.getMessages();

      if(messages.length == 0)
      {
        // don't think this will ever hit, but mehh
        Logger.log('warning: thread ' + thread.getId() + ' contains no messages, ignoring...');
        continue;
      }

      // TODO: LOOP THROUGH HERE UNTIL WE FIND THREAD WITH ATTACHMENT
      // (if usefirst then start at 1 till end, if not usefirst then start at end till 1)
      if(messages.length > 1)
      {
        //Logger.log('warning: thread ' + thread.getId() + ' has ' + thread.getMessageCount() + ' messages, ignoring...');
        Logger.log('warning: thread ' + thread.getId() + ' has ' + messages.length + ' messages, using ' + (usefirst ? 'first' : 'last') + ' message...');
        //continue;
      }

      // get the message
      var message = messages[usefirst ? 0 : (messages.length - 1)];

      // get the message attachments
      var attachments = message.getAttachments();

      // do we have none or too many attachments?
      if(attachments.length == 0 || attachments.length > 1)
      {
        Logger.log('warning: message ' + message.getSubject() + ' has ' + attachments.length + ' attachments, ignoring...');
        continue;
      }

      // return the attachment blob
      Logger.log('info: getLatestMailAttachment returning blob ' + attachments[0].getName() + ' with a size of ' + attachments[0].getSize() + ' bytes.');
      return attachments[0];
    }

    return null;
  }