* @deprecated in Drupal 8.0.x-dev, will be removed before Drupal 9.0.0.
* Instead, you should just check if a variable is an instance of
* \Drupal\Component\Render\MarkupInterface.
* @deprecated in Drupal 8.0.x-dev, will be removed before Drupal 9.0.0.
* Instead, you should just check if a variable is an instance of
* \Drupal\Component\Render\MarkupInterface.