public void save(String key, Object value) {
        Letter letter = root;
        for (int i = 0; i < key.length(); i++) {
            for (int j = 0; j < letter.subListCursor; j++) {
                if (letter.subList[j].key == key.charAt(i)) {
                    letter = letter.subList[j];
                    break;
                }
            }
            letter.subList[letter.subListCursor] = new Letter(key.charAt(i));
            letter.subListCursor++;
            letter = letter.subList[letter.subListCursor - 1];
        }
        letter.value = value;
    }