code: def test_get_latest_response_from_zero_responses(self):
      response = self.chatbot.get_latest_response("invalid")
  
      self.assertIsNone(response)
  
imports: from tests.base_case import ChatBotTestCase
  from chatterbot.logic import LogicAdapter
  from chatterbot.conversation import Statement
label_desc: Use image node_id 25 for calling the ChatterBotResponseTestCase obj's underlying member method code with example usage: obj.test_get_latest_response_from_zero_responses() without return types