code: def reserve(cls, queues, res, worker=None, timeout=10):
          
          if isinstance(queues, string_types):
              queues = [queues]
          queue, payload = res.pop(queues, timeout=timeout)
          if payload:
              return cls(queue, payload, res, worker)
docs: Reserve a job on one of the queues. This marks this job so
          that other workers will not pick it up.