[Notice] Trying to get property of non-object

GET /news-and-events/page-13/ics/753/20200508T-20200508T

Line 742 in /var/www/vhosts/barnsbury.surrey.sch.uk/public_html/event_calendar/code/Calendar.php

Source

733 			$id = str_replace("announcement-","",$id);
734 			$announcement = true;
735 		}
736 		else {
737 			$announcement = false;
738 		}
739 		if(is_numeric($id) && $oid) {
740 			if(!$feed) { 
741 				$event = DataObject::get_by_id($announcement ? $this->data()->getDateTimeClass() : $this->data()->getEventClass(), $id);
742 				$FILENAME = $announcement ? preg_replace("/[^a-zA-Z0-9s]/", "", $event->Title) : $event->URLSegment;
743 			}
744 			else {
745 				$FILENAME = preg_replace("/[^a-zA-Z0-9s]/", "", urldecode($_REQUEST['title']));
746 			}
747 
748 			$FILENAME .= ".ics";

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