Update app.py

app.py

@@ -273,11 +273,12 @@ def chatbot(query):
 
 
 def save_chat_to_file(chat_history):
-    timestamp = time.strftime("%Y%m%d-%H%M%S")  # Create a timestamp like 20250430-141522
-    filename = f"chat_history_{timestamp}.json"  # Unique filename
+    timestamp = time.strftime("%Y%m%d-%H%M%S")
+    filename = f"chat_history_{timestamp}.json"
     with open(filename, "w", encoding="utf-8") as f:
         json.dump(chat_history, f, ensure_ascii=False, indent=2)
     print(f"Chat history saved to {filename}")
+    return None  
 
 def ask(user_message, chat_history):
     if not user_message: