public function has($sourceName, $currencyCode, \DateTime $date = null, $rateType = RateType::MEDIAN)
    {
        if ($date === null) {
            $date = new \DateTime('now');
        }

        return array_key_exists($this->getRateKey($currencyCode, $date, $rateType, $sourceName), $this->rates);
    }
public function has($sourceName, $currencyCode, \DateTime $date = null, $rateType = RateType::MEDIAN)
    {
        if ($date === null) {
            $date = new \DateTime('now');
        }

        return array_key_exists($this->getRateKey($currencyCode, $date, $rateType, $sourceName), $this->rates);
    }
{@inheritdoc}