def pitch(self):
    """ Calculates the Pitch of the Quaternion. """

    x, y, z, w = self.x, self.y, self.z, self.w
    return math.atan2(2*x*w - 2*y*z, 1 - 2*x*x - 2*z*z)
Calculates the Pitch of the Quaternion.