Add pro level expire notice in admin bar for sub sites

add_action( 'admin_bar_menu', 'add_extension', 999 );

function add_extension($wp_admin_bar) {
    if( !is_main_site() ) {
    $id = get_current_blog_id();
    $expire = ProSites::get_expire($id);
    $diff = $expire - time();
    $years = floor($diff / (365*60*60*24));
    $months = floor(($diff - $years * 365*60*60*24) / (30*60*60*24));
    $days = floor(($diff - $years * 365*60*60*24 - $months*30*60*60*24)/ (60*60*24));

    $args = array(
        'id'    => 'pro_level',
        'title' => sprintf("Your Pro Level expires at %d years, %d months, %d days\n", $years, $months, $days),
        'parent' => 'top-secondary'
    );
    $wp_admin_bar->add_node( $args );
    }
}