code: protected function createDataItem($config = [])
      {
          if (!isset($config['class'])) {
              $config['class'] = $this->dataItemClass;
          }
          $config['dataSource'] = $this;
  
          return Yii::createObject($config);
      }
docs: [[@doctodo method_description:createDataItem]].
  
  @param array $config [[@doctodo param_description:config]] [optional]
  
  @return [[@doctodo return_type:createDataItem]] [[@doctodo return_description:createDataItem]]