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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 scopus_url(self):
 """URL to the abstract page on Scopus."""

        scopus_url = self.coredata.find('link[@rel="scopus"]', ns)
        try:
            return scopus_url.get('href')
        except AttributeError:  # scopus_url is None
            return None