[
    (None, 'Child 2', 'data1'),
    ('Child 1', 'Child 1.1', 'data2'),
    (None, 'Child 1', '')
]

[
        {
            'children': [],
            'data': ['data1'],
            'name': 'Child 2'
        },
        {
            'children': [
                 {
                     'children': [],
                     'data': ['data2'],
                     'name': 'Child 1.1'
                 }
            ],
            'data': [''],
            'name': 'Child 1'
        }
    ]

def create_tree(pairs):
    def node(): return [ROOT, [], []]
    table = defaultdict(node)
    # Build 2-way mapping between nodes
    for parent, child, data in pairs:
        table[parent][1].append(child)  # parent - > children
        table[child][0] = parent  # child -> parent
        table[parent][2].append(data)

    def follow(parent, childids):
        for content in childids:
            for name in content['items']:
                empty = []
                child = {
                    'name': name,
                    'children': empty,
                    'data': content['data']
                }
                parent.append(child)
                if name in table:
                    this_dict = [{
                        'items': table[name][1],
                        'data': table[name][2]
                    }]
                    follow(empty, this_dict)
    # Recursively fill in the tree
    tree = {ROOT: []}
    roots = [{'item': k, 'data': v[2]} for k, v in table.items() if v[0] == ROOT]
    my_root_items = [{
        'items': map(lambda s: s['item'], roots),
        'data': map(lambda s: s['data'], roots),
    }]
    follow(tree[ROOT], my_root_items)
    return tree[ROOT]