code: def mass_enclosed_2d(self, r, kwargs_profile):
          
          kwargs = copy.deepcopy(kwargs_profile)
          try:
              del kwargs['center_x']
              del kwargs['center_y']
          except:
              pass
          # integral of self.density_2d(x)* 2*np.pi * x *dx, 0, r
          out = integrate.quad(lambda x: self.density_2d(x, kwargs)*2*np.pi*x, 0, r)
          return out[0]
docs: computes the mass enclosed the projected line-of-sight
          :param r: radius (arcsec)
          :param kwargs_profile: keyword argument list with lens model parameters
          :return: projected mass enclosed radius r