Doubt in one function of "Yii by Example"

Im in page 98 of the ebook, and there’s an action to add in the Room controller:


public function actionLastReservationByRoomId($room_id)

    {

        $room = Room::findOne($room_id);

        $lastReservation = $room->lastReservation;


        return $this->render('lastReservationByRoomId',['room' => $room, 'lastReservation' => $lastReservation]);

    }

Im not sure what Room::findOne($room_id); do. If gets the room by ID, then why the next line does $room->lastReservation if the public function of the Room model to get the last reservation is getLastReservation() ?

The code works, but I want to understand what is doing :)

Active Record: Querying Data

Properties getters and setters

Active Record: Declaring Relations

Thanks!!

http://www.yiiframework.com/doc-2.0/yii-db-baseactiverecord.html#findOne()-detail

The missing part was that $room->lastReservation is the same that $room->getLastReservation(). That solved my doubt :)