protected static function IsWeekend(Datum $day)
 {
     return $day->Format("w") == 0 || $day->Format("w") == 6;
 }
/**
 * Smarty datum_format modifier plugin
 *
 * Type:     modifier<br>
 * Name:     datum_format<br>
 * Purpose:  format strings via datum_format
 * @param string
 * @param string
 * @return string
 */
function smarty_modifier_datum_format(Datum $datum)
{
    return $datum->Format();
}