Fatal error: Uncaught Error: Class 'Metadata\MergeableClassMetadata' not found in /home/esecureh/public_html/magdemo/vendor/jms/serializer/src/Metadata/ClassMetadata.php:22 Stack trace: #0 {main} thrown in /home/esecureh/public_html/magdemo/vendor/jms/serializer/src/Metadata/ClassMetadata.php on line 22