code: public void setPeriod(long duration, Chronology chrono) {
          chrono = DateTimeUtils.getChronology(chrono);
          setValues(chrono.get(this, duration));
      }
docs: Sets all the fields in one go from a millisecond duration.
  <p>
  When dividing the duration, only precise fields in the period type will be used.
  For large durations, all the remaining duration will be stored in the largest
  available precise field.
  
  @param duration  the duration, in milliseconds
  @param chrono  the chronology to use, null means ISO chronology
  @throws ArithmeticException if the set exceeds the capacity of the period