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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 format_url(self, url, **kwargs):
 # type: (str, Any) -> str """Format request URL with the client base URL, unless the supplied URL is already absolute. :param str url: The request URL to be formatted if necessary. """

        url = url.format(**kwargs)
        parsed = urlparse(url)
        if not parsed.scheme or not parsed.netloc:
            url = url.lstrip('/')
            base = self.config.base_url.format(**kwargs).rstrip('/')
            url = urljoin(base + '/', url)
        return url