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