docs: @Override
      public String sendMMS(String CorpNum, String sender, String receiver,
                            String receiverName, String subject, String content, File file,
                            Date reserveDT, String UserID) throws PopbillException {
  
          Message message = new Message();
  
          message.setSender(sender);
          message.setReceiver(receiver);
          message.setReceiverName(receiverName);
          message.setContent(content);
          message.setSubject(subject);
  
          return sendMMS(CorpNum, new Message[]{message}, file, reserveDT, UserID);
      }