Fatal error: Uncaught Error: Class "Drupal\migrate\ProcessPluginBase" not found in /home/www/drupal8/test/modules/migrate_plus/src/Plugin/migrate/process/MultipleValues.php:42
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/modules/migrate_plus/src/Plugin/migrate/process/MultipleValues.php on line 42