public function duplicateAction()
    {
        $id = $this->getRequest()->get($this->admin->getIdParameter());
        $object = $this->admin->getObject($id);
        $new = clone $object;

        $this->duplicateFiles($object, $new);

        $preResponse = $this->preDuplicate($new);
        if ($preResponse !== null) {
            return $preResponse;
        }

        return $this->createAction($new);
    }