new_contents: """Data utils"""
  
  class Lang:
      def __init__(self):
          self.word2index = {"SOS": 0, "EOS": 1, "COS": 2}
          self.word2count = {}
          self.index2word = {0: "SOS", 1: "EOS", 2: "COS"}
          self.n_words = 3
  
      def build_dict(self, sentence):
          for word in sentence:
              if word not in self.word2index:
                  self.word2index[word] = self.n_words
                  self.word2count[word] = 1
                  self.index2word[self.n_words] = word
                  self.n_words += 1
              else:
                  self.word2count[word] += 1
  
subject: Add util