• python – Visualize tree in bash, like the output of unix “tree” – Stack Overflow
• Build a Python Directory Tree Generator for the Command Line – Real Python

# tree.py

import six

branch = '├'
pipe = '|'
end = '└'
dash = '─'


class Tree(object):
    def __init__(self, tag):
        self.tag = tag


class Node(Tree):
    def __init__(self, tag, *nodes):
        super(Node, self).__init__(tag)
        self.nodes = list(nodes)


class Leaf(Tree):
    pass


def _draw_tree(tree, level, last=False, sup=[]):
    def update(left, i):
        if i < len(left):
            left[i] = '   '
        return left

    print(''.join(six.moves.reduce(update, sup, ['{}  '.format(pipe)] * level)) \
          + (end if last else branch) + '{} '.format(dash) \
          + str(tree.tag))
    if isinstance(tree, Node):
        level += 1
        for node in tree.nodes[:-1]:
            _draw_tree(node, level, sup=sup)
        _draw_tree(tree.nodes[-1], level, True, [level] + sup)


def draw_tree(trees):
    for tree in trees[:-1]:
        _draw_tree(tree, 0)
    _draw_tree(trees[-1], 0, True, [0])


class Track(object):
    def __init__(self, parent, idx):
        self.parent, self.idx = parent, idx


def parser(text):
    trees = []
    tracks = {}
    for line in text.splitlines():
        line = line.strip()
        key, value = map(lambda s: s.strip(), line.split(':', 1))
        nodes = value.split()
        if len(nodes):
            parent = Node(key)
            for i, node in enumerate(nodes):
                tracks[node] = Track(parent, i)
                parent.nodes.append(Leaf(node))
            curnode = parent
            if curnode.tag in tracks:
                t = tracks[curnode.tag]
                t.parent.nodes[t.idx] = curnode
            else:
                trees.append(curnode)
        else:
            curnode = Leaf(key)
            if curnode.tag in tracks:
                # well, how you want to handle it?
                pass # ignore
            else:
                trees.append(curnode)
    return trees

if __name__ == '__main__':
    text='''apple: banana eggplant
banana: cantaloupe durian
eggplant:
fig:'''
    draw_tree(parser(text))
    print()

    text='''apple: banana eggplant
banana: cantaloupe durian
eggplant:'''
    draw_tree(parser(text))
    print()

    text='''apple: banana
banana: cantaloupe durian
eggplant:'''
    draw_tree(parser(text))

> python .\tree.py
├─ apple
|  ├─ banana
|  |  ├─ cantaloupe
|  |  └─ durian
|  └─ eggplant
└─ fig

└─ apple
   ├─ banana
   |  ├─ cantaloupe
   |  └─ durian
   └─ eggplant

├─ apple
|  └─ banana
|     ├─ cantaloupe
|     └─ durian
└─ eggplant