code: def url_unquote(string, charset='utf-8', errors='replace', unsafe=''):
      
      rv = _unquote_to_bytes(string, unsafe)
      if charset is not None:
          rv = rv.decode(charset, errors)
      return rv
docs: URL decode a single string with a given encoding.  If the charset
      is set to `None` no unicode decoding is performed and raw bytes
      are returned.
  
      :param s: the string to unquote.
      :param charset: the charset of the query string.  If set to `None`
                      no unicode decoding will take place.
      :param errors: the error handling for the charset decoding.