'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.'

@classmethod
def from_settings(cls, settings):

    server = get_redis_from_settings(settings)
    key = (defaults.DUPEFILTER_KEY % {'timestamp': int(time.time())})
    debug = settings.getbool('DUPEFILTER_DEBUG')
    return cls(server, key=key, debug=debug)
