( ! ) Deprecated: Symfony\Component\Serializer\Mapping\ClassMetadata::__construct(): Implicitly marking parameter $classDiscriminatorMapping as nullable is deprecated, the explicit nullable type must be used instead in E:\Program_Files\wamp64\www\print\vendor\symfony\serializer\Mapping\ClassMetadata.php on line 54

( ! ) Deprecated: Symfony\Component\Serializer\Mapping\ClassMetadata::setClassDiscriminatorMapping(): Implicitly marking parameter $mapping as nullable is deprecated, the explicit nullable type must be used instead in E:\Program_Files\wamp64\www\print\vendor\symfony\serializer\Mapping\ClassMetadata.php on line 121

( ! ) Fatal error: Uncaught Error: Interface "Symfony\Component\Serializer\Mapping\ClassMetadataInterface" not found in E:\Program_Files\wamp64\www\print\vendor\symfony\serializer\Mapping\ClassMetadata.php on line 19
( ! ) Error: Interface "Symfony\Component\Serializer\Mapping\ClassMetadataInterface" not found in E:\Program_Files\wamp64\www\print\vendor\symfony\serializer\Mapping\ClassMetadata.php on line 19
Call Stack
#	Time	Memory	Function	Location
1	0.0024	378224	{main}( )	...\ClassMetadata.php:0