Update app.py

app.py

@@ -32,7 +32,7 @@ def respond(openai_apikey, chat_history):
         temperature=0.7
     )
     if not chat_history:
-        chat_history.apend([','])
+        chat_history.append([','])
     if chat_history[-1][1] is None:
         chat_history[-1][1] = ""
     for re_chunk in re_chat_completion.choices: