protected function _unmarkInternalTree()
    {
        $config = $this->getConfig();
        $this->_table->updateAll(
            function ($exp) use ($config) {
                /* @var \Cake\Database\Expression\QueryExpression $exp */
                $leftInverse = clone $exp;
                $leftInverse->setConjunction('*')->add('-1');
                $rightInverse = clone $leftInverse;

                return $exp
                    ->eq($config['leftField'], $leftInverse->add($config['leftField']))
                    ->eq($config['rightField'], $rightInverse->add($config['rightField']));
            },
            function ($exp) use ($config) {
                /* @var \Cake\Database\Expression\QueryExpression $exp */
                return $exp->lt($config['leftField'], 0);
            }
        );
    }