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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 probability_in(self, a, b):
 """ Returns the probability of a random variable falling between the given values. """

        if self.mean is None:
            return
        p1 = normdist(x=a, mu=self.mean, sigma=self.standard_deviation)
        p2 = normdist(x=b, mu=self.mean, sigma=self.standard_deviation)
        return abs(p1 - p2)