Fatal error: Uncaught Error: Interface "Drupal\workspaces\WorkspaceOperationInterface" not found in /home/www/drupal8/test/core/modules/workspaces/src/WorkspacePublisherInterface.php:10 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/workspaces/src/WorkspacePublisherInterface.php on line 10