def METHOD_NAME():
    grid = HexModelGrid((3, 3))
    z = grid.x_of_node
    steepest_slope = np.zeros(grid.number_of_nodes)
    receiver = np.arange(grid.number_of_nodes)
    receiver_link = np.full(grid.number_of_nodes, -1, dtype=int)
    active_links = np.arange(grid.number_of_links, dtype=int)
    _cfuncs.adjust_flow_receivers(
        grid.node_at_link_head,
        grid.node_at_link_tail,
        z,
        grid.calc_grad_at_link(z),
        active_links,
        receiver,
        receiver_link,
        steepest_slope,
    )
    assert_array_equal(receiver, [3, 0, 1, 3, 3, 4, 5, 3, 7, 8])
    assert_array_equal(
        receiver_link,
        [2, 0, 1, -1, 8, 9, 10, 11, 17, 18],
    )
    assert_array_almost_equal(steepest_slope, [0.5, 1, 1, 0, 1, 1, 1, 0.5, 1, 1])