code: def mass_enclosed_3d(self, r, kwargs_profile):
          
          kwargs = copy.deepcopy(kwargs_profile)
          try:
              del kwargs['center_x']
              del kwargs['center_y']
          except:
              pass
          # integral of self._profile.density(x)* 4*np.pi * x^2 *dx, 0,r
          out = integrate.quad(lambda x: self._profile.density(x, **kwargs)*4*np.pi*x**2, 0, r)
          return out[0]
docs: computes the mass enclosed within a sphere of radius r
          :param r: radius (arcsec)
          :param kwargs_profile: keyword argument list with lens model parameters
          :return: 3d mass enclosed of r