public function returnType($type = null)
    {
        deprecationWarning(
            'TypedResultTrait::returnType() is deprecated. ' .
            'Use TypedResultTrait::setReturnType()/getReturnType() instead.'
        );
        if ($type !== null) {
            $this->_returnType = $type;

            return $this;
        }

        return $this->_returnType;
    }