Add OPENAI_API_KEY prompt info

app.py

@@ -23,7 +23,7 @@ with gr.Blocks(title="ChatGPT 助手") as demo:
 
     def ask(message, chat_history):
         if openai.api_key is None:
-            chat_history.append((message, "Error: No OpenAI API Key found. Please enter your key in the cell above."))
+            chat_history.append((message, "Please paste your OpenAI key to use"))
         else:
             bot_message = conv.ask(message)
             chat_history.append((message, bot_message))