code: def main():
      
      args = parser.parse_args()
  
      scheduler = Scheduler()
  
      print 'Start %s' % scheduler.scheduler_id
      scheduler.interval = args.interval
      if args.keepalive:
          scheduler.run(once=True)
          keepalive = Job('simplescheduler.keepalive',
                          args=[0,
                                scheduler.get_running_scheduler_id(),
                                args.interval * 2])
          scheduler.schedule(keepalive, long(time.time() * 1000000))
      scheduler._run()
docs: SimpleScheduler
      redis parameters will be read from environment variables:
      REDIS_HOST, REDIS_PORT, REDIS_DB, REDIS_KEY (password)