public static function getLevelCode(
        /*# string */ $level
    )/*# : int */ {
        if (is_string($level) &&
            isset(self::$levels[$level])) {
            return self::$levels[$level];
        }

        throw new Exception\InvalidArgumentException(
            Message::get(
                Message::INVALID_LOG_LEVEL,
                (string) $level
            ),
            Message::INVALID_LOG_LEVEL
        );
    }