<?phpnamespaceDotdigitalgroup\Email\Model\Sql;useZend\Stdlib\JsonSerializable;/** * Class is wrapper over Zend_Db_Expr for implement JsonSerializable interface. */classExpressionextends\Zend_Db_ExprimplementsJsonSerializable{/** * @inheritdoc */publicfunctionjsonSerialize(){return['class'=>static::class,'arguments'=>['expression'=>$this->_expression,],];}}