code: def add_word(self, word):
      cur = self.root
      for letter in word:
          if letter not in cur.children:
              cur.children[letter] = TrieNode(letter)
          cur = cur.children[letter]
      cur.is_terminal = True
  
file_path: keon-algos/algorithms/tree/trie/add_and_search.py
imports: import collections
label_desc: Use image node_id 2 for calling the WordDictionary obj's underlying member method code with example usage: obj.add_word(word) without return types