code: def aliasByNode(requestContext, seriesList, *nodes):
      
      for series in seriesList:
          pathExpression = _getFirstPathExpression(series.name)
          metric_pieces = pathExpression.split('.')
          series.name = '.'.join(metric_pieces[n] for n in nodes)
      return seriesList
docs: Takes a seriesList and applies an alias derived from one or more "node"
      portion/s of the target name. Node indices are 0 indexed.
  
      Example::
  
          &target=aliasByNode(ganglia.*.cpu.load5,1)