public function addValidators()
    {
        \Validator::extendImplicit('gallery_required', function ($attribute, $value, $parameters, $validator) {
            /* @var Validator $validator */

            if (class_exists($parameters[0])) {
                $model = new $parameters[0];
                // we need to build the model
                $model->fill(request()->all());
                if (method_exists($model, 'getRequiredImages')) {
                    return $model->hasFieldValue($attribute);
                }
            }

            return false;
        }, trans('validation.required'));
    }