public function outputError($error)
    {
        $message = self::ESCAPE . self::RED;
        if (is_scalar($error)) {
            $message .= $error;
        } else {
            if (is_object($error) && $error instanceof \Exception) {
                $message .= '#' . $error->getCode() . ': ' . $error->getMessage();
            }
        }
        $message .= PHP_EOL;
        $message .= self::ESCAPE . self::NORMAL;
        fwrite(STDERR, $message);
    }