diff --git a/src/routers/scene_router.py b/src/routers/scene_router.py
index a95e07e..a5df17b 100644
--- a/src/routers/scene_router.py
+++ b/src/routers/scene_router.py
@@ -85,7 +85,7 @@ async def add(r: AddObjectDTO, background_tasks: BackgroundTasks):
 
 
 @router.post("/buy-slot/{player_id}")
-async def buy_slot(player_id: str):
+async def buy_slot(player_id: str) -> None:
     logger.debug(f"Starting to buy slot for player {player_id}")
     player = state.scene.get_player(player_id)
     if player is None: