i have install tree view extension from kartik. I follow the documentations, but i'm not able to create the root node. My model extends active record and this is the code:

<?php

namespace common\models;

use Yii;
use yii\db\ActiveRecord;
use yii\behaviors\TimestampBehavior;

class Pages extends ActiveRecord
{

    use \kartik\tree\models\TreeTrait;

        /**
     * @var string the classname for the TreeQuery that implements the NestedSetQueryBehavior.
     * If not set this will default to `kartik  ree\models\TreeQuery`.
     */
    public static $treeQueryClass; // change if you need to set your own TreeQuery
 
    /**
     * @var bool whether to HTML encode the tree node names. Defaults to `true`.
     */
    public $encodeNodeNames = true;
 
    /**
     * @var bool whether to HTML purify the tree node icon content before saving.
     * Defaults to `true`.
     */
    public $purifyNodeIcons = true;
 
    /**
     * @var array activation errors for the node
     */
    public $nodeActivationErrors = [];
 
    /**
     * @var array node removal errors
     */
    public $nodeRemovalErrors = [];
 
    /**
     * @var bool attribute to cache the `active` state before a model update. Defaults to `true`.
     */
    public $activeOrig = true;
    

    /**
     * {@inheritdoc}
     */
    public static function tableName()
    {
        return 'pages';
    }

    public function behaviors( ) {
        return [
            [
                'class' => TimestampBehavior::class,
                'attributes' => [
                    ActiveRecord::EVENT_BEFORE_INSERT => ['created_at','updated_at'],
                    ActiveRecord::EVENT_BEFORE_UPDATE => ['updated_at'],
                ],
            ],    
           
        ];
    }

    /**
     * {@inheritdoc}
     */
    public function rules()
    {
        return [
            [['pages_name', 'pages_tag'], 'required'],
            [['pages_visibility', 'created_at', 'updated_at'], 'integer'],
            [['pages_meta_description', 'pages_meta_keywords'], 'string'],
            [['pages_name', 'pages_tag','pages_meta_title'], 'string', 'max' => 255],
        ];
    }

    /**
     * {@inheritdoc}
     */
    public function attributeLabels()
    {
        return [
            'id' => Yii::t('backend', 'ID'),
            'pages_name' => Yii::t('backend', 'Pages Name'),
            'pages_tag' => Yii::t('backend', 'Pages Tag'),
            'pages_visibility' => Yii::t('backend', 'Pages Visibility'),
            'pages_meta_description' => Yii::t('backend', 'Pages Meta Description'),
            'pages_meta_keywords' => Yii::t('backend', 'Pages Meta Keywords'),
            'pages_meta_title' => Yii::t('backend', 'Pages Meta Title'),
            'created_at' => Yii::t('backend', 'Created At'),
            'updated_at' => Yii::t('backend', 'Updated At'),
        ];
    }
    
    /**
     *  Relation with junction table pagesxblock many to many with Block table
     */
    public function getBlocks() {
        return $this->hasMany(Block::className(), ['id' => 'id_block'])
        ->viaTable('pagesxblock', ['id_pages' => 'id']);
    }

My controller is :

public function actionTree()
    {

        return $this->render('tree', []); 
    }

When i visit the view all works but if i try to create a root i get this error in my console browser

{"out":"Calling

unknown method: common\models\Pages::isLeaf()","status":"error"}

UPDATE I isolated the part of the code that gives me the error and refers to this inside the model:

 public function behaviors( ) {
        return [
            [
                'class' => TimestampBehavior::class,
                'attributes' => [
                    ActiveRecord::EVENT_BEFORE_INSERT => ['created_at','updated_at'],
                    ActiveRecord::EVENT_BEFORE_UPDATE => ['updated_at'],
                ],
            ],    
            
        ];
    }