$dtstart = $component->__get("DTSTART");
$firstOccurence = $dtstart->getDateTime()->getTimeStamp();
// Finding the last occurence is a bit harder
if (!$component->__get("RRULE")) {
$lastOccurence = self::getDtEndTimeStamp($component);
} else {
$dtstart = $component->__get("DTSTART");
$firstOccurence = $dtstart->getDateTime()->getTimeStamp();
// Finding the last occurence is a bit harder
if (!$component->__get("RRULE")) {
$lastOccurence = self::getDtEndTimeStamp($component);
} else {