code: def test_get_latest_response_from_zero_responses(self):
      response = self.chatbot.get_latest_response("invalid")
  
      self.assertIsNone(response)
  
imports: from tests_django.base_case import ChatterBotTestCase
  from chatterbot.conversation import Statement
label_desc: Use image node_id 23 for calling the ChatBotTests obj's underlying member method code with example usage: obj.test_get_latest_response_from_zero_responses() without return types