Fatal error: Uncaught Error: Class "Drupal\Core\Entity\ContentEntityBase" not found in /home/www/drupal8/test/core/modules/menu_link_content/src/Entity/MenuLinkContent.php:58 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/menu_link_content/src/Entity/MenuLinkContent.php on line 58