public function exchange($price, $baseCurrency, $toBeExchanged)
{
    $exchangeRate = $this->list[$baseCurrency->getCode()]->getExchangeRates()[$toBeExchanged->getCode()]->getRate();
    $total = $price * $exchangeRate;
    return number_format($total, 2); // Sonucu formatlayarak döndür
}