History error fix

app.py

@@ -16,6 +16,10 @@ def respond(
     temperature,
     top_p,
 ):
+    # Initialize history if it is None
+    if history is None:
+        history = []
+
     try:
         # Format the chat history for the DialoGPT model using the 'messages' format
         conversation = [{"role": "system", "content": system_message}]