def mass_3d_lens(self, r, sigma0, Rs):
        """
        mass enclosed a 3d sphere or radius r for lens parameterisation
        :param sigma0:
        :param Rs:
        :return:
        """
        rho0 = self.sigma2rho(sigma0, Rs)
        return self.mass_3d(r, rho0, Rs)
def mass_3d_lens ( self , r , sigma0 , Rs ) : rho0 = self . sigma2rho ( sigma0 , Rs ) return self . mass_3d ( r , rho0 , Rs )
mass enclosed a 3d sphere or radius r for lens parameterisation
        :param sigma0:
        :param Rs:
        :return: