/**
  * Provide extra classes which can be set on the outer block level.
  * @param array $classes - map of css-class => display-title suitable for us in a listbox/dropdown
  * @return void
  */
 public function provideLayoutCSSClasses(array &$classes = [])
 {
     parent::provideCSSClasses($classes);
 }
 /**
  * Provide extra classes from config.extra_css_classes which can be set on the inner block (not container) level.
  * @param array $classes - map of css-class => display-title suitable for us in a listbox/dropdown
  * @return void
  */
 public function providePresentationCSSClasses(array &$classes = [])
 {
     parent::provideCSSClasses($classes);
 }