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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def variance(array):
 """ Return the variance of a list of divisible numbers. """

    if len(array) < 2:
        return 0
    u = mean(array)
    return sum([(x - u) ** 2 for x in array]) / (len(array) - 1)