code: def create_response(self, message=None, end_session=False, card_obj=None,
                          reprompt_message=None, is_ssml=None):
          
          response = dict(self.base_response)
          if message:
              response['response'] = self.create_speech(message, is_ssml)
          response['response']['shouldEndSession'] = end_session
          if card_obj:
              response['response']['card'] = card_obj
          if reprompt_message:
              response['response']['reprompt'] = self.create_speech(reprompt_message, is_ssml)
          return Response(response)
docs: message - text message to be spoken out by the Echo
          end_session - flag to determine whether this interaction should end the session
          card_obj = JSON card object to substitute the 'card' field in the raw_response