docs: private static Currency createCurrency(
        String commonCode, String name, String unicode, String... alternativeCodes) {
  
      CurrencyAttributes attributes =
          new CurrencyAttributes(commonCode, name, unicode, alternativeCodes);
  
      Currency currency = new Currency(commonCode, attributes);
  
      for (String code : attributes.codes) {
        if (commonCode.equals(code)) {
          // common code will always be part of the currencies map
  
          currencies.put(code, currency);
  
        } else if (!currencies.containsKey(code)) {
          // alternative codes will never overwrite common codes
  
          currencies.put(code, new Currency(code, attributes));
        }
      }
  
      return currency;
    }