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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 branch(self, name):
 """Get the branch ``name`` of this repository. :param str name: (required), branch name :type name: str :returns: :class:`Branch <github3.repos.branch.Branch>` """

        json = None
        if name:
            url = self._build_url('branches', name, base_url=self._api)
            json = self._json(self._get(url), 200)
        return Branch(json, self) if json else None