diff --git a/app/main.py b/app/main.py
index 0e3ede8a..b330073a 100644
--- a/app/main.py
+++ b/app/main.py
@@ -3,7 +3,7 @@
 from app.classes.shop import Shop
 
 
-def shop_trip():
+def shop_trip() -> None:
     config = util.parse_json("app/config.json")
 
     fuel_price = config["FUEL_PRICE"]