Sometimes I encounter a public static function `create()` in plugin classes, for the example in the code show in [Tutorial on Using Drupal 8 Plugin Derivatives Effectively][1]. ```php public static function create(ContainerInterface $container, $base_plugin_id) { return new static( $container->get('entity.manager')->getStorage('node') ); } ``` Could you clarify me what the purpose of that function is, for example what it should do and where it's used? [1]: https://www.sitepoint.com/tutorial-on-using-drupal-8-plugin-derivatives-effectively/