def potential(self, x, y, kwargs, k=None):
        """
        lensing potential

        :param x: x-position (preferentially arcsec)
        :type x: numpy array
        :param y: y-position (preferentially arcsec)
        :type y: numpy array
        :param kwargs: list of keyword arguments of lens model parameters matching the lens model classes
        :param k: only evaluate the k-th lens model
        :return: lensing potential in units of arcsec^2
        """
        return self.lens_model.potential(x, y, kwargs, k=k)
def potential ( self , x , y , kwargs , k = None ) : return self . lens_model . potential ( x , y , kwargs , k = k )
lensing potential

        :param x: x-position (preferentially arcsec)
        :type x: numpy array
        :param y: y-position (preferentially arcsec)
        :type y: numpy array
        :param kwargs: list of keyword arguments of lens model parameters matching the lens model classes
        :param k: only evaluate the k-th lens model
        :return: lensing potential in units of arcsec^2