def listGetShiftedGeometricMean(listofnumbers, shiftby=10.0):
    """ Return the shifted geometric mean of a list of numbers, where the additional shift defaults to
    10.0 and can be set via shiftby
    """
    geommean = 1.0
    nitems = 0
    for number in listofnumbers:
        nitems = nitems + 1
        nextnumber = number + shiftby
        geommean = pow(geommean, (nitems - 1) / float(nitems)) * pow(nextnumber, 1 / float(nitems))
    return geommean - shiftby