Уведомление PHP Notice: Undefined index

PHP Notice:  Undefined index: is_fixed in /system/controllers/dating/backend/grids/grid_dating_aims.php on line 37, referer: https://мой_домен/admin/controllers/edit/dating/dating_aims

$actions = array(
        array(
            'title' => LANG_EDIT,
            'class' => 'edit',
            'href' => href_to($controller->root_url, 'meeting_aim_edit', array('{id}')),
        ),
        array(
            'title' => LANG_DELETE,
            'class' => 'delete',
            'href' => href_to($controller->root_url, 'meeting_aim_delete', array('{id}')),
            'confirm' => LANG_BACKEND_DELETE_MEETING_AIM,
            'handler' => function($row){
                return !$row['is_fixed']; /*строка 37*/
            }
        )
    );

<?php
 
function grid_dating_aims($controller){
 
    $options = array(
        'is_sortable' => true,
        'is_pagination' => false,
        'is_draggable' => true,
        'order_by' => 'id',
        'order_to' => 'asc',
        'show_id' => true
    );
 
    $columns = array(
        'id' => array(
            'title' => 'id',
            'width' => 30,
        ),
        'title' => array(
            'title' => LANG_DATING_AIM,
            'href' => href_to($controller->root_url, 'dating_aim_edit', array('{id}')),
        )
    );
 
    $actions = array(
        array(
            'title' => LANG_EDIT,
            'class' => 'edit',
            'href' => href_to($controller->root_url, 'dating_aim_edit', array('{id}')),
        ),
        array(
            'title' => LANG_DELETE,
            'class' => 'delete',
            'href' => href_to($controller->root_url, 'dating_aim_delete', array('{id}')),
            'confirm' => LANG_BACKEND_DELETE_DATING_AIM,
            'handler' => function($row){
                return !$row['is_fixed'];
            }
        )
    );
 
    return array(
        'options' => $options,
        'columns' => $columns,
        'actions' => $actions
    );
 
}
 
 

<?php
 
class actionDatingDatingAimEdit extends cmsAction {
 
    public function run($aim_id){
 
		if (!$aim_id) { cmsCore::error404(); }
		$dating_model = cmsCore::getModel('dating');
		$form = $this->getForm('dating_aim', array('edit'));
		$is_submitted = $this->request->has('submit');
 
		$aim = $dating_model->getDatingAim($aim_id);
 
		if ($is_submitted){
 
			$aim = $form->parse($this->request, $is_submitted);
			$errors = $form->validate($this, $aim);
 
			if (!$errors){
				$dating_model->updateDatingAim($aim_id, $aim);
				cmsUser::addSessionMessage(LANG_BACKEND_EDIT_DATING_AIM_SUCCESS, 'success');
				$this->redirectToAction('dating_aims');
			}
			if ($errors){
				cmsUser::addSessionMessage(LANG_FORM_ERRORS, 'error');
			}
 
		}
 
		return cmsTemplate::getInstance()->render('backend/dating_aim', array(
			'do' => 'edit',
			'aim' => $aim,
			'form' => $form,
			'errors' => isset($errors) ? $errors : false
		));
 
    }
 
}