code: def isUnique(self, word):
      """
      check if a word is unique.
      :type word: str
      :rtype: bool
      """
      abb = self.getAbb(word)
      hasAbbr = self.abb_dic.get(abb, None)
      return hasAbbr == None or (hasAbbr and word in self.dictionary)
  
label_desc: Use image node_id 2 for calling the ValidWordAbbr obj's underlying member method code with example usage: obj.isUnique(word) and returns: unknown