Fatal error: Uncaught Error: Class "Facebook\GraphNodes\Collection" not found in /home2/cp334332/public_html/examcenter/vendor/facebook/graph-sdk/src/Facebook/GraphNodes/GraphNode.php:31 Stack trace: #0 {main} thrown in /home2/cp334332/public_html/examcenter/vendor/facebook/graph-sdk/src/Facebook/GraphNodes/GraphNode.php on line 31