public function init(){
    add_action('widgets_init', array($this, 'registerSidebars'),20);
}

public function registerSidebars(){
    $args = array(
        'name'          => __('Page Middle Sidebar %d', APP_TD),
            'id'            => 'page-middle-sidebar',
        'description'   => __('This sidebar is used to place the add in page content above and below', APP_TD),
        'class'         => '',
        'before_widget' => '<li id="%1$s" class="widget %2$s">',
        'after_widget'  => '</li>',
        'before_title'  => '<h2 class="widgettitle">',
        'after_title'   => '</h2>' );
    register_sidebars(2, $args);
}