Update app.py

app.py

@@ -118,24 +118,17 @@ with gr.Blocks() as demo:
 
     with gr.Row():
         with gr.Column(scale=2):
-            chatbot = gr.Chatbot(
-                value=[
-                    {"role": "user", "content": "Hello"},
-                    {"role": "assistant", "content": "Hi"}
-                ],
-                label="Chatbot"
-            )
+            chatbot = gr.Chatbot([{"role": "user", "content": "Hello"}, {"role": "assistant", "content": "Hi"}], label="Chatbot")
             chat_btn = gr.Button("Add messages")
 
             def chat(history):
                 time.sleep(2)
-                return history + [
-                    {"role": "user", "content": "How are you?"},
-                    {"role": "assistant", "content": "I am good."}
-                ]
+                yield [{"role": "user", "content": "How are you?"}, {"role": "assistant", "content": "I am good."}]
 
             chat_btn.click(
-                chat,
+                lambda history: history
+                + [{"role": "user", "content": "How are you?"}, {"role": "assistant", "content": "I am good."}]
+                + (time.sleep(2) or []),
                 chatbot,
                 chatbot,
             )