public function ImportForm()
    {
        $form = parent::ImportForm();
        if (!$form) {
            return;
        }

        $form->unsetAllActions();
        $newActionList = new FieldList(array(
            new FormAction('import', _t('AdvancedWorkflowAdmin.IMPORT', 'Import workflow'))
        ));
        $form->Fields()->fieldByName('_CsvFile')->getValidator()->setAllowedExtensions(array('yml', 'yaml'));
        $form->Fields()->removeByName('EmptyBeforeImport');
        $form->setActions($newActionList);

        return $form;
    }