Fatal error: Uncaught Error: Class "JMS\Serializer\AbstractVisitor" not found in /home/kiwakim/stock/vendor/jms/serializer/src/JMS/Serializer/XmlSerializationVisitor.php:17 Stack trace: #0 {main} thrown in /home/kiwakim/stock/vendor/jms/serializer/src/JMS/Serializer/XmlSerializationVisitor.php on line 17