Fatal error: Uncaught Error: Class "Metadata\MergeableClassMetadata" not found in C:\xampp\htdocs\electronica\vendor\jms\security-extra-bundle\JMS\SecurityExtraBundle\Metadata\ClassMetadata.php:32 Stack trace: #0 {main} thrown in C:\xampp\htdocs\electronica\vendor\jms\security-extra-bundle\JMS\SecurityExtraBundle\Metadata\ClassMetadata.php on line 32