public function MessageGetThreadsById($thread_ids)
 {
     // $thread_ids : string or string array
     $this->CheckAndSetHeader(__FUNCTION__);
     $reg_args["thread_id"] = $this->getRegularArgs($thread_ids, __FUNCTION__);
     $this->encodeString($reg_args);
     $results = parent::MessageGetThreadsById($reg_args);
     $this->methodClose();
     return $this->decodeString($results->thread);
 }