Sugested change¶

1. Create the protected property valid_content_type on class \ShopContentContentControl
2. Change the method \ShopContentContentControl::get_content_data to check if the property content_type was set, if so, check if the field valid_content_type is included in $valid_content_type on the SQL query.
3. Change the method *** \ShopContentContentControl::set_validation_rules*** to add validation to the field valid_content_type as array.
4. Change the file src/shop_content.php to add the flowing property to the object:

$coo_shop_content_control->set_('valid_content_type', ['content', 'file']);