Update app.py

app.py

@@ -94,7 +94,7 @@ with gr.Blocks() as demo:
 
     with gr.Tab("Keep Alive"):
         gr.Textbox(label="Ping", value="ping", interactive=False)
-        gr.Button("Ping").click(keep_alive, inputs=None, outputs=None)
+        gr.Button("Ping").click(keep_alive, inputs=None, outputs="pong")
 
 # Enable request queue (multi-user safe)
 demo.queue()  # simple queue; compatible with current Gradio versions