def retrieve_work
      collect_dead_jobs!
      work = retrieve_op.perform(ordered_queues, expire_at)
      return UnitOfWork.new(*work, in_flight_keymaker: keymaker) if work

      sleep(poll_interval)
      nil
    end
def retrieve_work
      collect_dead_jobs!
      work = retrieve_op.perform(ordered_queues, expire_at)
      return UnitOfWork.new(*work, in_flight_keymaker: keymaker) if work

      sleep(poll_interval)
      nil
    end
seconds