public function tieWith($conjunction = null)
    {
        deprecationWarning(
            'QueryExpression::tieWith() is deprecated. ' .
            'Use QueryExpression::setConjunction()/getConjunction() instead.'
        );
        if ($conjunction !== null) {
            return $this->setConjunction($conjunction);
        }

        return $this->getConjunction();
    }