Fatal error: Uncaught Error: Class 'yii\db\ActiveRecord' not found in /var/www/html/autocar/vendor/creocoder/yii2-nested-sets/tests/models/MultipleTree.php:22 Stack trace: #0 {main} thrown in /var/www/html/autocar/vendor/creocoder/yii2-nested-sets/tests/models/MultipleTree.php on line 22