public function formatTreeList(Query $query, array $options = [])
    {
        return $query->formatResults(function ($results) use ($options) {
            /* @var \Cake\Collection\CollectionTrait $results */
            $options += [
                'keyPath' => $this->_getPrimaryKey(),
                'valuePath' => $this->_table->getDisplayField(),
                'spacer' => '_',
            ];

            return $results
                ->listNested()
                ->printer($options['valuePath'], $options['keyPath'], $options['spacer']);
        });
    }