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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 sigma2_R(self, R, kwargs_mass, kwargs_light, kwargs_anisotropy):
 """ returns unweighted los velocity dispersion for a specified projected radius :param R: 2d projected radius (in angular units) :param kwargs_mass: mass model parameters (following lenstronomy lens model conventions) :param kwargs_light: deflector light parameters (following lenstronomy light model conventions) :param kwargs_anisotropy: anisotropy parameters, may vary according to anisotropy type chosen. We refer to the Anisotropy() class for details on the parameters. :return: """

        I_R_sigma2 = self.I_R_simga2(R, kwargs_mass, kwargs_light, kwargs_anisotropy)
        I_R = self.lightProfile.light_2d(R, kwargs_light)
        return I_R_sigma2 / I_R