Fatal error: Uncaught Error: Class "Drupal\Core\Entity\EntityConfirmFormBase" not found in /home/www/drupal8/test/modules/migrate_tools/src/Form/MigrationDeleteForm.php:16 Stack trace: #0 {main} thrown in /home/www/drupal8/test/modules/migrate_tools/src/Form/MigrationDeleteForm.php on line 16