Fatal error: Uncaught Error: Class "yii\helpers\StringHelper" not found in /var/www/html/prod/vendor/engmohamedamer/yii2-enhanced-gii/crud/simple/controller.php:12 Stack trace: #0 {main} thrown in /var/www/html/prod/vendor/engmohamedamer/yii2-enhanced-gii/crud/simple/controller.php on line 12