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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 pmf(value):
 """ Comvert a string into a Probability Mass Function. :param value: a sequence of probabilities summing up to 1 (no commas) :returns: [(0.157, 0), (0.843, 1)] """

    probs = probabilities(value)
    if abs(1.-sum(map(float, value.split()))) > 1e-12:
        raise ValueError('The probabilities %s do not sum up to 1!' % value)
    return [(p, i) for i, p in enumerate(probs)]