public function get_setting() {
        $result = $this->config_read($this->name);
        if (is_null($result)) {
            return NULL;
        }
        if ($result === '') {
            return array();
        }
        $settings = array();
        for ($i=0; $i<7; $i++) {
            if ($result & (1 << $i)) {
                $settings[] = $i;
            }
        }
        return $settings;
    }