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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 finish(self):
 """ Parse the buffered response body, rewrite its URLs, write the result to the wrapped request, and finish the wrapped request. """

        stylesheet = ''.join(self._buffer)
        parser = CSSParser()
        css = parser.parseString(stylesheet)
        replaceUrls(css, self._replace)
        self.request.write(css.cssText)
        return self.request.finish()