code: def sigma_s2(self, r, R, kwargs_profile, kwargs_anisotropy, kwargs_light):
          
          beta = self.anisotropy.beta_r(r, kwargs_anisotropy)
          return (1 - beta * R**2/r**2) * self.sigma_r2(r, kwargs_profile, kwargs_anisotropy, kwargs_light)
docs: projected velocity dispersion
          :param r:
          :param R:
          :param r_ani:
          :param a:
          :param gamma:
          :param phi_E:
          :return: