docs: def add_to_starred(self, starred):
          """
          :calls: `PUT /user/starred/:owner/:repo <http://developer.github.com/v3/activity/starring>`_
          :param starred: :class:`github.Repository.Repository`
          :rtype: None
          """
          assert isinstance(starred, github.Repository.Repository), starred
          headers, data = self._requester.requestJsonAndCheck(
              "PUT",
              "/user/starred/" + starred._identity
          )