Fatal error: Uncaught Error: Class 'yii\web\JsExpression' not found in /opt/lampp/htdocs/squidv2-stage-cr/vendor/execut/yii2-widget-bootstraptreeview/examples/example-simple.php:30 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/squidv2-stage-cr/vendor/execut/yii2-widget-bootstraptreeview/examples/example-simple.php on line 30