code: def from_settings(cls, settings):
          
          server = get_redis_from_settings(settings)
          # XXX: This creates one-time key. needed to support to use this
          # class as standalone dupefilter with scrapy's default scheduler
          # if scrapy passes spider on open() method this wouldn't be needed
          # TODO: Use SCRAPY_JOB env as default and fallback to timestamp.
          key = defaults.DUPEFILTER_KEY % {'timestamp': int(time.time())}
          debug = settings.getbool('DUPEFILTER_DEBUG')
          return cls(server, key=key, debug=debug)
docs: Returns an instance from given settings.
  
          This uses by default the key ``dupefilter:<timestamp>``. When using the
          ``scrapy_redis.scheduler.Scheduler`` class, this method is not used as
          it needs to pass the spider name in the key.
  
          Parameters
          ----------
          settings : scrapy.settings.Settings
  
          Returns
          -------
          RFPDupeFilter
              A RFPDupeFilter instance.