class TrieNode(object):

    def __init__(self):
        self.nodes = [None] * 26  # 1 for each letter in alphabet
        self.terminating = False  # Flag to determine termination

    def insert(self, word):
        word = word.lower()
        index = ord(word[0]) - 97  # Remove 97 to make it a-z = 0-25

        # If the indexue of the child node at the index is None, make a new trie
        #  there to represent the letter
        if self.nodes[index] is None:
            self.nodes[index] = TrieNode()

        # if the word length is greater 1, then we are still adding the word.
        #  otherwise, set the terminating flag to True so we know a word ends here.
        if len(word) > 1:
            self.nodes[index].insert(word[1:])
        else:
            self.nodes[index].terminating = True

    def has(self, word):
        word = word.lower()
        word_len = len(word)
        index = ord(word[0]) - 97

        if self.nodes[index] is not None and word_len > 1:
            return self.nodes[index].has(word[1:])
        elif self.nodes[index].terminating is True and word_len == 1:
            return True

        return False

    @classmethod
    def from_file(cls, fname):
        node = cls()
        with open(fname, 'r') as fh:
            for line in fh.readlines():
                pass
        return node

    def to_file(self, fname):
        def inner(node, path):
            for index, node in enumerate(node.nodes):
                if node is not None:
                    path += [index]
                    if node.terminating:
                        yield path, node.terminating
                    for item in inner(node, path):
                        yield item
                    path.pop()

        with open(fname, 'w') as fh:
            for path, terminating in inner(self, []):
                print(f"{path!r}{int(terminating)}\n")

testing_words = ["testings","test","testing","tesla","teslas","master","masters","bar"]
t = TrieNode()
for word in testing_words:
    t.insert(word)
for word in testing_words:
    assert t.has(word)

t.to_file("testing.out")
# TrieNode.from_file("testing.out")