code: def _normalize_string(raw_str):
    
    return " ".join(
        token.strip()
        for token in tokenizer.encode(text_encoder.native_to_unicode(raw_str)))
docs: Normalizes the string using tokenizer.encode.
  
    Args:
      raw_str: the input string
  
    Returns:
     A string which is ready to be tokenized using split()