Fatal error: Uncaught Error: Class 'yii\base\Behavior' not found in /var/www/html/autocar/vendor/kotchuprik/yii2-sortable-widgets/behaviors/Sortable.php:9 Stack trace: #0 {main} thrown in /var/www/html/autocar/vendor/kotchuprik/yii2-sortable-widgets/behaviors/Sortable.php on line 9