code: public CalendarPeriod GetCalendarPeriod()
  	{
  		CalendarPeriod res = new CalendarPeriod();
  		List<Period> periods = new ArrayList<Period>();
  		for( int i = 0; i < this.periods.size(); i++ )
  		{
  			PeriodAssociative<T> p = this.periods.get( i );
  			periods.add( new Period( p.getFrom(), p.getTo() ) );
  		}
  		// use merge to merge jointed periods...
  		res.setPeriods( res._Merge( periods ) );
  
  		return res;
  	}
docs: returns the same but with no values, and with the periods merged