Import page not showing in october cms

Question

I'm trying to create an import page as described in this documentation page https://octobercms.com/docs/backend/import-export For now i can not see the import page

the import export config file

import:
    title: Import z pliku xsl,xslx
    modelClass: Depcore\Parts\Models\PartImport
    list: $/depcore/parts/models/part/columns.yaml
    redirect: depcore/parts/parts

export:
    title: Eksport części
    modelClass: Depcore\Parts\Models\PartImport
    list: $/depcore/parts/models/part/columns.yaml
    redirect: depcore/parts/parts

The Part model

use Backend\Classes\Controller; use BackendMenu;

class Parts extends Controller
{
    public $implement = ['Backend\Behaviors\ListController','Backend\Behaviors\FormController','Backend\Behaviors\ReorderController','Backend\Behaviors\ImportExportController'];

    public $listConfig = 'config_list.yaml';
    public $formConfig = 'config_form.yaml';
    public $reorderConfig = 'config_reorder.yaml';
    public $importExportConfig = 'config_import_export.yaml';

    public function __construct()
    {
        parent::__construct();
        BackendMenu::setContext('depcore.parts', 'parts', 'side-menu-item2');
    }
}

The file PartImport.php (made for now as in the documentation)

<?php
namespace depcore\parts\Models;

class PartImport extends \Backend\Models\ImportModel{
    /**
     * @var array The rules to be applied to the data.
     */
    public $rules = [];

    public function importData($results, $sessionKey = null) {

      foreach ($results as $row => $data) {

        try {
            // $subscriber = new Subscriber;
            // $subscriber->fill($data);
            // $subscriber->save();

            // $this->logCreated();
        }
        catch (\Exception $ex) {
            $this->logError($row, $ex->getMessage());
        }

      }
    }
}

The import.htm file is exactly as described in the documentation.

Maybe I'm missing something but I cant see the import or export buttons on the toolbar.