code: def format_delay(self, delay, limit, bucket, environ, start_response):
          
  
          # Set up the default status
          status = self.conf.status
  
          # Set up the retry-after header...
          headers = HeadersDict([('Retry-After', "%d" % math.ceil(delay))])
  
          # Let format fiddle with the headers
          status, entity = limit.format(status, headers, environ, bucket,
                                        delay)
  
          # Return the response
          start_response(status, headers.items())
          return entity
docs: Formats the over-limit response for the request.  May be
          overridden in subclasses to allow alternate responses.