    tree = vtkTree()
    success = tree.CheckedShallowCopy(graph)
    print('Success?', success)
    # std::cout << 'Success? ' << success << std::endl

    treeLayoutView = vtkGraphLayoutView()
--
    tree = vtkTree()
    valid_tree = tree.CheckedShallowCopy(graph)
    if not valid_tree:
        print('Invalid tree')
        return

