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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 repository(self, owner, repository):
 """Returns a Repository object for the specified combination of owner and repository :param str owner: (required) :param str repository: (required) :returns: :class:`Repository <github3.repos.Repository>` """

        json = None
        if owner and repository:
            url = self._build_url('repos', owner, repository)
            json = self._json(self._get(url), 200)
        return Repository(json, self) if json else None