/**
  * Generate navigation tabs HTML, based on a specific admin menu.
  * @access  public
  * @since   1.0.0
  * @return  string/WP_Error
  */
 public static function get_navigation_tabs($menu_key = 'woothemes')
 {
     $html = '';
     $screens = Woothemes_Updater_Screen::get_available_screens();
     $current_tab = self::get_current_screen();
     if (0 < count($screens)) {
         foreach ($screens as $k => $v) {
             $class = 'nav-tab';
             if ($current_tab == $k) {
                 $class .= ' nav-tab-active';
             }
             $url = add_query_arg('page', 'woothemes-helper', network_admin_url('index.php'));
             $url = add_query_arg('screen', $k, $url);
             $html .= '<a href="' . esc_url($url) . '" class="' . esc_attr($class) . '">' . esc_html($v) . '</a>';
         }
     }
     return $html;
 }