Fatal error: Uncaught Error: Class "JMS\Serializer\Metadata\ClassMetadata" not found in /home/kiwakim/stock/vendor/jms/serializer/tests/Metadata/Driver/php/ObjectWithXmlKeyValuePairs.php:7 Stack trace: #0 {main} thrown in /home/kiwakim/stock/vendor/jms/serializer/tests/Metadata/Driver/php/ObjectWithXmlKeyValuePairs.php on line 7