code: def density_2d(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(np.sqrt(x^2+r^2))* dx, 0, infty
          out = integrate.quad(lambda x: 2*self._profile.density(np.sqrt(x**2+r**2), **kwargs), 0, 100)
          return out[0]
docs: computes the projected density along the line-of-sight
          :param r: radius (arcsec)
          :param kwargs_profile: keyword argument list with lens model parameters
          :return: 2d projected density at projected radius r