def METHOD_NAME(grids: list[pp.Grid, pp.MortarGrid]) -> None:
    """Test whether a not implemented error is raised.
    The error should be raised when a face-centered quantity is passed together with
    a mortar grid.
    Parameters:
        grids: List of grids. The first element is a two-dimensional subdomain grid,
            and the second element is an interface grid. See the fixture grids().
    """
    msg = "Interface variables can only be cell-centered."
    with pytest.raises(NotImplementedError) as excinfo:
        # Attempt to compute the error for a face-centered quantity on a mortar grid
        pp.error_computation.l2_error(
            grid=grids[1],
            true_array=np.ones(6),
            approx_array=np.random.random(6),
            is_cc=False,
            is_scalar=True,
        )
    assert msg in str(excinfo.value