code: def release_to_branch(self, release_id):
          
          self.ensure_release_scheme('branches')
          return self.releases[release_id].revision.branch
docs: Shortcut to translate a release identifier to a branch name.
  
          :param release_id: A :attr:`Release.identifier` value (a string).
          :returns: A branch name (a string).
          :raises: :exc:`~exceptions.TypeError` when :attr:`release_scheme` isn't
                   'branches'.