private function prepareCrumb($model, $callable, $isRoot, $isLeaf)
    {
        return $callable ? $callable($model, $isRoot, $isLeaf) : $model->{$this->titleField};
    }
private function prepareCrumb($model, $callable, $isRoot, $isLeaf)
    {
        return $callable ? $callable($model, $isRoot, $isLeaf) : $model->{$this->titleField};
    }
private function prepareCrumb ( $ model , $ callable , $ isRoot , $ isLeaf ) { return $ callable ? $ callable ( $ model , $ isRoot , $ isLeaf ) : $ model -> { $ this -> titleField } ; }
Output model as crumb
@param \yii\db\ActiveRecord $model
@param callable $callable
@param boolean $isRoot
@param boolean $isLeaf
@return string
Output model as crumb