def METHOD_NAME(document, comm):
    grid_box = GridBox(Div(), Div(), Div(), Div(), Div(), Div(), Div(), Div(), ncols=3)
    model = grid_box.get_root(document, comm=comm)
    assert len(model.children) == 8
    coords = [
        (0, 0, 1, 1), (0, 1, 1, 1), (0, 2, 1, 1),
        (1, 0, 1, 1), (1, 1, 1, 1), (1, 2, 1, 1),
        (2, 0, 1, 1), (2, 1, 1, 1)
    ]
    for child, coord in zip(model.children, coords):
        assert child[1:] == coord