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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 average(old_avg, current_value, count):
 """ Calculate the average. Count must start with 0 3.23 1.0 3.0 """

    if old_avg is None:
        return current_value
    return (float(old_avg) * count + current_value) / (count + 1)