public function onLogicalExpression($expressionType, $left, $right) {
        switch ($expressionType) {
            case ExpressionType::AND_LOGICAL:
//				return '$logicalAnd('.$left.', '.$right.')';
                return $this->_prepareBinaryExpression(self::LOGICAL_AND, $left, $right);
                break;
            case ExpressionType::OR_LOGICAL:
//				return '$logicalOr('.$left.', '.$right.')';
                return $this->_prepareBinaryExpression(self::LOGICAL_OR, $left, $right);
                break;
            default:
                throw new \InvalidArgumentException('onLogicalExpression');
        }
    }