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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 radius(self, angle):
 """ Calculate the polar radius for a given polar angle. Parameters angle : float The polar angle (radians). Returns ------- radius : float The polar radius (pixels). """


        return (self.sma * (1. - self.eps) /
                np.sqrt(((1. - self.eps) * np.cos(angle))**2 +
                        (np.sin(angle))**2))