public function onBeforeDelete()
    {
        // If a reservation is deleted remove the names from the guest list
        foreach ($this->Attendees() as $attendee) {
            /** @var Attendee $attendee */
            if ($attendee->exists()) {
                $attendee->delete();
            }
        }

        // Remove the folder
        if (($folder = Folder::get()->find('Name', $this->ReservationCode)) && $folder->exists() && $folder->isEmpty()) {
            $folder->delete();
        }

        parent::onBeforeDelete();
    }