Tries 2

trie.py

class Trie(object):
    ...
    def all_suffixes(self, prefix):
        results = set()
        if self.flag:
            results.add(prefix)
        if not self.children: return results
        return reduce(lambda a, b: a | b, [node.all_suffixes(prefix + char) for (char, node) in self.children.items()]) | results

    def autocomplete(self, prefix):
        node = self
        for char in prefix:
            if char not in node.children:
                return set()
            node = node.children[char]
        return list(node.all_suffixes(prefix))