code: def start(self, stop_event):
      raise NotImplementedError
  
imports: import time
  from mindsdb_sql.parser.ast import Identifier, Select, Insert
  from mindsdb.utilities import log
  from mindsdb.utilities.context import context
  from .types import ChatBotMessage, BotException
label_desc: Use image node_id 2 for calling the BasePolling obj's underlying member method code with example usage: obj.start(stop_event) without return types