public function cancelTask($task_id)
    {
        if (empty($task_id)) {
            throw new \InvalidArgumentException("Please set task_id");
        }
        $url = "projects/{$this->project_id}/tasks/$task_id/cancel";
        $request = array();

        $this->setCommonHeaders();
        $res = $this->apiCall(self::POST, $url, $request);
        return self::json_decode($res);
    }