public function getCurrencySymbol($currencyCode = null): string
    {
        if (!extension_loaded('intl')) {
            throw new InvalidConfigException('Locale component requires PHP intl extension to be installed.');
        }

        $locale = $this->locale;

        if ($currencyCode !== null) {
            $locale = $locale->withCurrency($currencyCode);
        }

        $formatter = new NumberFormatter((string)$locale, NumberFormatter::CURRENCY);
        return $formatter->getSymbol(NumberFormatter::CURRENCY_SYMBOL);
    }