diff --git a/files/lib/data/room/RoomCache.class.php b/files/lib/data/room/RoomCache.class.php
index 48a4439..b7f4f65 100644
--- a/files/lib/data/room/RoomCache.class.php
+++ b/files/lib/data/room/RoomCache.class.php
@@ -47,11 +47,8 @@ protected function init()
 
     /**
      * Returns a specific room.
-     *
-     * @param   integer     $roomID
-     * @return  Room
      */
-    public function getRoom($roomID)
+    public function getRoom(int $roomID): ?Room
     {
         if (isset($this->rooms[$roomID])) {
             return $this->rooms[$roomID];