$callback = function ( $old = null, &$ttl = null ) {
$bar = [];
$this->addToSidebar( $bar, 'sidebar' );
Hooks::run( 'SkinBuildSidebar', [ $this, &$bar ] );
$callback = function ( $old = null, &$ttl = null ) {
$bar = [];
$this->addToSidebar( $bar, 'sidebar' );
Hooks::run( 'SkinBuildSidebar', [ $this, &$bar ] );