d6.py

class Node(object):
    def __init__(self, name, weight, children):
        self.name = name
        self.weight = weight
        self.children = children

def parse(content):
    queue = {}
    for l in content.split('\n'):
        if l.strip() != '':
            words = l.split(' ')
            name = words[0]
            weight = int(words[1][1:-1])
            children = []
            print('.', l)
            if len(words[2:]) > 0:
                while len(words[2:]) > 1:
                    w = words.pop()
                    if w.endswith(','):
                        w = w[:-1]
                    children.append(w)
            queue[name] = (Node(name, weight, []), children)
    return queue

with open('d6in.txt') as f:
    queue = parse(f.read())

while len(queue) > 1:
    for (k, v) in queue.items():
        if len(v[1]) > 0:
            while len(v[1]) > 0:
                n = v[1].pop()
                a = queue[n]
                v[0].children.append(a)
                del queue[n]
            break