code: def map(self, timeout=None, max_concurrency=64, auto_batch=True):
          
          return self.get_routing_client(auto_batch).map(
              timeout=timeout, max_concurrency=max_concurrency)
docs: Shortcut context manager for getting a routing client, beginning
          a map operation and joining over the result.  `max_concurrency`
          defines how many outstanding parallel queries can exist before an
          implicit join takes place.
  
          In the context manager the client available is a
          :class:`MappingClient`.  Example usage::
  
              results = {}
              with cluster.map() as client:
                  for key in keys_to_fetch:
                      results[key] = client.get(key)
              for key, promise in results.iteritems():
                  print '%s => %s' % (key, promise.value)