/**
  * Specify data which should be serialized to JSON
  * @link http://php.net/manual/en/jsonserializable.jsonserialize.php
  * @return mixed data which can be serialized by <b>json_encode</b>,
  * which is a value of any type other than a resource.
  * @since 5.4.0
  */
 public function jsonSerialize()
 {
     $arr = parent::jsonSerialize();
     $vars = get_object_vars($this);
     return array_merge($vars, $arr);
 }