src/ApiClient.php
public function getExchangeRates(array $currencyPairs)
    {
        $currencySymbols = array_map(function (array $currencies) {
            return implode($currencies).self::CURRENCY_SYMBOL_SUFFIX; // Currency pairs are suffixed with "=X"
        }, $currencyPairs);

        return $this->fetchQuotes($currencySymbols);
    }
public function getExchangeRates(array $currencyPairs)
    {
        $currencySymbols = array_map(function (array $currencies) {
            return implode($currencies).self::CURRENCY_SYMBOL_SUFFIX; // Currency pairs are suffixed with "=X"
        }, $currencyPairs);

        return $this->fetchQuotes($currencySymbols);
    }
Retrieves currency exchange rates. Accepts concatenated ISO 4217 currency codes such as "GBPUSD".

@param array $currencyPairs List of pairs of currencies

@return array|Quote[]