code: def search(self, input_statement, **additional_parameters):
          
          self.chatbot.logger.info('Beginning search for close text match')
  
          input_search_text = input_statement.search_text
  
          if not input_statement.search_text:
              self.chatbot.logger.warn(
                  'No value for search_text was available on the provided input'
              )
  
              input_search_text = self.chatbot.storage.tagger.get_bigram_pair_string(
                  input_statement.text
              )
  
          search_parameters = {
              'search_text_contains': input_search_text,
              'persona_not_startswith': 'bot:',
              'page_size': self.search_page_size
          }
  
          if additional_parameters:
              search_parameters.update(additional_parameters)
  
          statement_list = self.chatbot.storage.filter(**search_parameters)
  
          closest_match = Statement(text='')
          closest_match.confidence = 0
  
          self.chatbot.logger.info('Processing search results')
  
          # Find the closest matching known statement
          for statement in statement_list:
              confidence = self.compare_statements(input_statement, statement)
  
              if confidence > closest_match.confidence:
                  statement.confidence = confidence
                  closest_match = statement
  
                  self.chatbot.logger.info('Similar text found: {} {}'.format(
                      closest_match.text, confidence
                  ))
  
                  yield closest_match
docs: Search for close matches to the input. Confidence scores for
          subsequent results will order of increasing value.
  
          :param input_statement: A statement.
          :type input_statement: chatterbot.conversation.Statement
  
          :param **additional_parameters: Additional parameters to be passed
              to the ``filter`` method of the storage adapter when searching.
  
          :rtype: Generator yielding one closest matching statement at a time.