code: def encode(self, s):
      
      return [int(w) + self._num_reserved_ids for w in s.split()]
docs: Transform a human-readable string into a sequence of int ids.
  
      The ids should be in the range [num_reserved_ids, vocab_size). Ids [0,
      num_reserved_ids) are reserved.
  
      EOS is not appended.
  
      Args:
        s: human-readable string to be converted.
  
      Returns:
        ids: list of integers