Working on prefix search problem and the problem is, given a set of words, for example words = ['a', 'apple', 'angle', 'angel', 'bat', 'bats'], for any given prefix, find all matched words. For example, if input is ang, return 'angle', 'angel', if no match, return an empty list [].

Here is my code and any advice on performance improvement in terms of algorithm time complexity (not sure if Trie Tree is the best solution), code bugs or general advice on code style is highly appreciated.

Source code in Python 2.7,

from collections import defaultdict
class TrieNode:
    def __init__(self):
        self.children = defaultdict(TrieNode)
        self.isEnd = False
    def insert(self, word):
        node = self
        for w in word:
            node = node.children[w]
        node.isEnd = True
    def search(self, word):
        node = self
        for w in word:
            if w in node.children:
                node = node.children[w]
            else:
                return []
        # prefix match
        # traverse currnt node to all leaf nodes
        result = []
        self.traverse(node, list(word), result)
        return [''.join(r) for r in result]

    def traverse(self, root, prefix, result):
        if root.isEnd:
            result.append(prefix[:])
        for c,n in root.children.items():
            prefix.append(c)
            self.traverse(n, prefix, result)
            prefix.pop(-1)
if __name__ == "__main__":
    words = ['a', 'apple', 'angle', 'angel', 'bat', 'bats']
    root = TrieNode()
    for w in words:
        root.insert(w)
    print root.search('a') # 'a', 'apple', 'angle', 'angel'
    print root.search('ang') # 'angle', 'angel'
    print root.search('angl') # 'angle'
    print root.search('z') # []