public function getAvailableCurrencies() : array
    {
        if ($this->isPartial) {
            foreach ($this->currencyData as $currencyCode => $data) {
                if (! isset($this->currencies[$currencyCode])) {
                    $this->currencies[$currencyCode] = new Currency(... $data);
                }
            }

            ksort($this->currencies);

            $this->isPartial = false;
        }

        return $this->currencies;
    }