docs: public long getDateTimeMillis(int year, int monthOfYear, int dayOfMonth,
                                    int millisOfDay)
          throws IllegalArgumentException
      {
          long instant = year().set(0, year);
          instant = monthOfYear().set(instant, monthOfYear);
          instant = dayOfMonth().set(instant, dayOfMonth);
          return millisOfDay().set(instant, millisOfDay);
      }