code: def to_tokens(self, indices):
          
  
          to_reduce = False
          if not isinstance(indices, list):
              indices = [indices]
              to_reduce = True
  
          max_idx = len(self.idx_to_token) - 1
  
          tokens = []
          for idx in indices:
              if not isinstance(idx, int) or idx > max_idx:
                  raise ValueError('Token index %d in the provided `indices` is invalid.' % idx)
              else:
                  tokens.append(self.idx_to_token[idx])
  
          return tokens[0] if to_reduce else tokens
docs: Converts token indices to tokens according to the vocabulary.
  
  
          Parameters
          ----------
          indices : int or list of ints
              A source token index or token indices to be converted.
  
  
          Returns
          -------
          str or list of strs
              A token or a list of tokens according to the vocabulary.