public function revisionShow($openy_upgrade_log_revision) {
    $openy_upgrade_log = $this->entityManager()->getStorage('openy_upgrade_log')->loadRevision($openy_upgrade_log_revision);
    $view_builder = $this->entityManager()->getViewBuilder('openy_upgrade_log');

    return $view_builder->view($openy_upgrade_log);
  }