code: public CurrencyUnitBuilder setCurrencyCode(String currencyCode) {
          Objects.requireNonNull(currencyCode, "currencyCode required");
          this.currencyCode = currencyCode;
          this.currencyContext = CurrencyContextBuilder.of(getClass().getSimpleName()).build();
          return this;
      }
docs: Allows to set the currency code, for creating multiple instances, using one Builder.
  
  @param currencyCode the (unique) and identifying currency code, not null.
  @return the Builder, for chaining.
  @see javax.money.CurrencyUnit#getCurrencyCode()