Fatal error: Uncaught Error: Class "Drupal\Core\Entity\ContentEntityBase" not found in /home/www/drupal8/test/core/modules/workspaces/src/Entity/WorkspaceAssociation.php:40 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/workspaces/src/Entity/WorkspaceAssociation.php on line 40