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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def url_unquote(string, charset='utf-8', errors='replace', unsafe=''):
 """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. """

    rv = _unquote_to_bytes(string, unsafe)
    if charset is not None:
        rv = rv.decode(charset, errors)
    return rv