def averageSeries(requestContext, *seriesLists):
    if not seriesLists or not any(seriesLists):
        return []
    seriesList, start, end, step = normalize(seriesLists)
    name = "averageSeries(%s)" % formatPathExpressions(seriesList)
    values = (safeDiv(safeSum(row), safeLen(row))
              for row in zip_longest(*seriesList))
    series = TimeSeries(name, start, end, step, values)
    series.pathExpression = name
    return [series]
.. todo::
dataset/ETHPy150Open brutasse/graphite-api/graphite_api/functions.py/averageSeries--crossover with--dataset/ETHPy150Open lisa-lab/pylearn2/pylearn2/models/dbm/ising.py/IsingHidden.expected_energy_term