Fatal error: Uncaught Error: Class "Metadata\MergeableClassMetadata" not found in /home/kiwakim/stock/vendor/jms/serializer/src/JMS/Serializer/Metadata/ClassMetadata.php:16 Stack trace: #0 {main} thrown in /home/kiwakim/stock/vendor/jms/serializer/src/JMS/Serializer/Metadata/ClassMetadata.php on line 16