code: public static CurrencyUnit getCurrency(String currencyCode, String... providers) {
          return Optional.ofNullable(MONETARY_CURRENCIES_SINGLETON_SPI()).orElseThrow(
                  () -> new MonetaryException("No MonetaryCurrenciesSingletonSpi loaded, check your system setup."))
                  .getCurrency(currencyCode, providers);
      }
docs: Access a new instance based on the currency code. Currencies are
  available as provided by {@link CurrencyProviderSpi} instances registered
  with the {@link javax.money.spi.Bootstrap}.
  
  @param currencyCode the ISO currency code, not {@code null}.
  @param providers    the (optional) specification of providers to consider.
  @return the corresponding {@link CurrencyUnit} instance.
  @throws UnknownCurrencyException if no such currency exists.