/**
  * Initialize the upgrader.
  *
  * This will set the relationship between the skin being used and this upgrader,
  * and also add the generic strings to `WP_Upgrader::$strings`.
  *
  * @since 2.8.0
  */
 public function init()
 {
     $this->skin->set_upgrader($this);
     $this->generic_strings();
 }