@Override
  public ActionResponse delete(String tenantId, String userId) {
    checkNotNull(tenantId);

    return ToActionResponseFunction.INSTANCE.apply(
        delete(Void.class, uri("/os-quota-sets/%s", tenantId))
            .param(userId != null, "user_id", userId)
            .executeWithResponse());
  }
  @Override
  public ActionResponse update(String stackName, String stackId, StackUpdate stackUpdate) {
    checkNotNull(stackName);
    checkNotNull(stackId);
    checkNotNull(stackUpdate);

    return ToActionResponseFunction.INSTANCE.apply(
        put(Void.class, uri("/stacks/%s/%s", stackName, stackId))
            .entity(stackUpdate)
            .executeWithResponse());
  }