code: public Emoji getEmoji(String unicode) {
      Node tree = root;
      for (char c : unicode.toCharArray()) {
        if (!tree.hasChild(c)) {
          return null;
        }
        tree = tree.getChild(c);
      }
      return tree.getEmoji();
    }
docs: Finds Emoji instance from emoji unicode
  @param unicode unicode of emoji to get
  @return Emoji instance if unicode matches and emoji, null otherwise.