add update constraint when id does not exist

handler.py

@@ -59,6 +59,12 @@ def index(crud):
     elif crud == "update":
         food_id = payload["id"]
         food = payload["food"]
+
+        if len(data["foods"]) <= food_id:
+            result["status"] = "error"
+            result["message"] = f"{food_id} does not exist."
+            return json.dumps(result, indent = 2).encode()
+        
         data["foods"][food_id] = food
 
         result["status"] = "success"