Update app.py

app.py

@@ -10,7 +10,7 @@ def random_response(message, history):
     if history:
         messages.extend(history)
 
-    messages.append(:"role": "user", "content": message)
+    messages.append({"role": "user", "content": message})
 
     response = client.chat_completion(
         messages,