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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 roll(self):
 """ Calculates the Roll of the Quaternion. """


    x, y, z, w = self.x, self.y, self.z, self.w
    return math.atan2(2*y*w - 2*x*z, 1 - 2*y*y - 2*z*z)