it should work

app.py

@@ -1,11 +1,11 @@
 import gradio as gr
 import random
 
-def echo(message, history):
+def random_message(message, history):
     choices = ["yes", "no"]
     random_choices = random.choice(choices)
     return random_choices
 
-chatbot = gr.ChatInterface(echo, type = "message")
+chatbot = gr.ChatInterface(random_message, type = "messages")
 
 chatbot.launch()