public function cleanUp()
 {
     parent::cleanUp();
     if (isset($this->image)) {
         imagedestroy($this->image);
     }
     $this->owner = null;
     $this->parent = null;
     $this->descendents = null;
 }
 public function cleanUp()
 {
     parent::cleanUp();
     $this->owner = null;
     $this->a = null;
     $this->b = null;
     $this->parent = null;
     $this->descendents = null;
 }