code: def countSeries(requestContext, *seriesLists):
      
      if not seriesLists or not any(seriesLists):
          series = constantLine(requestContext, 0).pop()
          series.pathExpression = "countSeries()"
      else:
          seriesList, start, end, step = normalize(seriesLists)
          name = "countSeries(%s)" % formatPathExpressions(seriesList)
          values = (int(len(row)) for row in zip_longest(*seriesList))
          series = TimeSeries(name, start, end, step, values)
          series.pathExpression = name
  
      return [series]
docs: Draws a horizontal line representing the number of nodes found in the
      seriesList.
  
      Example::
  
          &target=countSeries(carbon.agents.*.*)