Fatal error: Uncaught Error: Class "yii\helpers\StringHelper" not found in C:\xampp\htdocs\arthurkotsch.online\vendor\yiisoft\yii2-gii\src\generators\crud\default\views\index.php:9 Stack trace: #0 {main} thrown in C:\xampp\htdocs\arthurkotsch.online\vendor\yiisoft\yii2-gii\src\generators\crud\default\views\index.php on line 9