def add_semantic_hub_layout(cx, hub):
    """Attach a layout aspect to a CX network given a hub node."""
    graph = cx_to_networkx(cx)
    hub_node = get_node_by_name(graph, hub)
    node_classes = classify_nodes(graph, hub_node)
    layout_aspect = get_layout_aspect(hub_node, node_classes)
    cx['cartesianLayout'] = layout_aspect
Attach a layout aspect to a CX network given a hub node.