Update app_2.py

app_2.py

@@ -5,7 +5,7 @@ from google.genai import types
 client = genai.Client(api_key=os.environ["GEMINI_API_KEY"])
 MODEL = "gemini-3.1-flash-lite-preview"
 
-def model_chat(message, state):
+def model_chat(message, history, state):  # <- 3 args!
     if state is None:
         state = {"chat": client.chats.create(model=MODEL), "lock": threading.Lock()}