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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 FinalizeTransferUrl(self, url):
 """Modify the url for a given transfer, based on auth and version."""

        url_builder = _UrlBuilder.FromUrl(url)
        if self.global_params.key:
            url_builder.query_params['key'] = self.global_params.key
        return url_builder.url