Update app.py

app.py

@@ -54,6 +54,8 @@ with gr.Blocks(css = "custom.css") as demo:
                     history.append([ele])
                 else:
                     history[-1].append(ele)
+        if len(history[-1]) <= 1:
+            return ""
         history[-1][1] = ""
         user_message_ = history[-1][0]
         pred_iter = predict(user_message_ ,history)