def mapSeries(requestContext, seriesList, mapNode):
  """
  Short form: ``map()``

  Takes a seriesList and maps it to a list of seriesList. Each seriesList has the
  given mapNode in common.

  .. note:: This function is not very useful alone. It should be used with :py:func:`reduceSeries`

  .. code-block:: none

    mapSeries(servers.*.cpu.*,1) =>

      [
        servers.server1.cpu.*,
        servers.server2.cpu.*,
        ...
        servers.serverN.cpu.*
      ]
  """
  metaSeries = {}
  keys = []
  for series in seriesList:
    key = series.name.split(".")[mapNode]
    if key not in metaSeries:
      metaSeries[key] = [series]
      keys.append(key)
    else:
      metaSeries[key].append(series)
  return [ metaSeries[k] for k in keys ]