code: public final PeriodList getConsumedTime(final Date rangeStart,
              final Date rangeEnd) {
          return getConsumedTime(rangeStart, rangeEnd, true);
      }
docs: Returns a normalised list of periods representing the consumed time for this event.
  @param rangeStart the start of a range
  @param rangeEnd the end of a range
  @return a normalised list of periods representing consumed time for this event
  @see VEvent#getConsumedTime(Date, Date, boolean)