def METHOD_NAME(self, values):
    """Gives the (sub/super)gradient of the atom w.r.t. each argument.
    Matrix expressions are vectorized, so the gradient is a matrix.
    Args:
        values: A list of numeric values for the arguments.
    Returns:
        A list of SciPy CSC sparse matrices or None.
    """
    # Grad: jth largest element of w is placed at the index of the jth largest element of x
    x, w_padded = self._get_args_from_values(values)
    indices = np.argsort(x)
    n = len(x)
    sorted_w = np.sort(w_padded)
    return [sp.csc_matrix((sorted_w, (indices, np.zeros(n))), shape=(n, 1))]