code: public static CurrencyUnit removeCurrencyUnit(String currencyCode) {
          Objects.requireNonNull(currencyCode);
          return ConfigurableCurrencyUnitProvider.CURRENCY_UNITS.remove(currencyCode);
      }
docs: Removes a CurrencyUnit.
  
  @param currencyCode the currency code, not null.
  @return any unit instance removed, or null.