Common/EventListener/AbstractSaleListener.php
protected function updateExchangeRate(SaleInterface $sale)
    {
        if (null !== $sale->getExchangeRate()) {
            return false;
        }

        $date = $sale->getExchangeDate() ?? new \DateTime();

        $rate = $this->currencyConverter->getRate(
            $this->currencyConverter->getDefaultCurrency(),
            $sale->getCurrency()->getCode(),
            $date
        );

        $sale
            ->setExchangeRate($rate)
            ->setExchangeDate($date);

        return true;
    }
protected function updateExchangeRate(SaleInterface $sale)
    {
        if (null !== $sale->getExchangeRate()) {
            return false;
        }

        $date = $sale->getExchangeDate() ?? new \DateTime();

        $rate = $this->currencyConverter->getRate(
            $this->currencyConverter->getDefaultCurrency(),
            $sale->getCurrency()->getCode(),
            $date
        );

        $sale
            ->setExchangeRate($rate)
            ->setExchangeDate($date);

        return true;
    }
Sets the sale's exchange rate.

@param SaleInterface $sale

@return bool