EventAttendeesUpdate::getEventPreviousAttendees

protected function getEventPreviousAttendees(int $parentEventId): array
{
	$events = EventTable::query()
		->addSelect('OWNER_ID')
		->addFilter('DELETED', 'N')
		->addFilter('PARENT_ID', $parentEventId)
		->addFilter('CAL_TYPE', CoreEventToolsDictionary::CALENDAR_TYPE['user'])
		->fetchAll()
	;
	$previousAttendees = [];
	foreach ($events as $event)
	{
		$previousAttendees[] = (int)$event['OWNER_ID'];
	}

	return $previousAttendees;
}