Date_Holidays_Filter_Whitelist | --Date_Holidays_Filter_Portugal_Official
By Carlos Pires; based on Ireland/Official.php by Ken Guest.
Date_Holidays_Filter_Portugal_Official Date_Holidays_Filter_Portugal_Official( )
Only accepts official Portugal public holidays as described on https://www.bmf.gv.at/Finanzministerium/GesetzlicheFeiertag_4523/_start.htm
Date_Holidays_Filter_Portugal_Official __construct( )