protected function provideUuidKey($model)
    {
        // provide a UUID only if increment is disabled
        if ($model->incrementing === false) {
            $key = $model->getKeyName();

            if (empty($model->$key)) {
                $model->$key = (string)Uuid::uuid4();
            }
        } else {
            throw new RuntimeException(
              sprintf('$incrementing must be false on class "%s" to support uuid', get_class($this))
            );
        }
    }