code: public String format(String worldName, Currency currency, double balance) {
          return format(worldName, currency, balance, displayFormat);
      }
docs: Format a balance to a readable string with the default formatting.
  
  @param worldName The world Name associated with this balance
  @param currency  The currency instance associated with this balance.
  @param balance   The balance.
  @return A pretty String showing the balance. Returns a empty string if currency is invalid.