Update app.py

app.py

@@ -62,7 +62,7 @@ class ChatbotAPP:
         self.service = self.get_drive_service()  # Google Drive service instance
         self.app = self.create_app()  # Gradio app instance
         self.chat_log_name = ""  # Filename for the chat log
-        self.start_time=None #save the chat session start
+        self.start_time=0 #save the chat session start
 
     # Method to create Google Drive service instance
     def get_drive_service(self):