code: public static Media mediaUploadnews(String access_token, String messageJson) {
          return MediaAPI.mediaUploadnews(access_token, messageJson);
      }
docs: 高级群发 构成 MassMPnewsMessage 对象的前置请求接口
  
  @param access_token access_token
  @param messageJson  messageJson
  @return result