code: def get_default_response(self, input_statement):
          
          from random import choice
  
          if self.default_responses:
              response = choice(self.default_responses)
          else:
              try:
                  response = self.chatbot.storage.get_random()
              except StorageAdapter.EmptyDatabaseException:
                  response = input_statement
  
          self.chatbot.logger.info(
              'No known response to the input was found. Selecting a random response.'
          )
  
          # Set confidence to zero because a random response is selected
          response.confidence = 0
  
          return response
docs: This method is called when a logic adapter is unable to generate any
          other meaningful response.