code: def unicode_to_bytes(s, encoding='utf-8', errors='replace'):
      
      return s if isinstance(s, str) else s.encode(encoding, errors)
docs: Helper to convert unicode strings to bytes for data that needs to be
      written to on output stream (i.e. terminal)
      For Python 3 this should be called str_to_bytes
  
      :param str s: string to encode
      :param str encoding: utf-8 by default
      :param str errors: what to do when encoding fails
      :return: byte string utf-8 encoded