Drupal creating a third level tabs

function yourmodulename_menu() {
  $items = array();
  $items['user/%user/level1'] = array(
    'type' => MENU_LOCAL_TASK,
    'weight' => 1,
  );
 
  $items['user/%user/level1/level2'] = array(
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => 0,
  );
  $items['user/%user/level1/level2'] = array(
    'type' => MENU_LOCAL_TASK,
    'weight' => 0,
  );
  $items['user/%user/level1/level2/level3'] = array(
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => 0,
  );
  $items['user/%user/level1/level2/level3'] = array(
    'type' => MENU_LOCAL_TASK,
    'weight' => 0,
  );
  return $items;
}

function yourmodulename_local_tasks() {
  $router_item = menu_get_item();
  if (!$router_item || !$router_item['access']) {
    return '';
  }
  // send the path if there is no arg 4 (we assume this is already the tab parent
  // else send the tab parent url
  $router = (arg(4)) ?  $router_item['tab_parent'] : $router_item['path'];
 
 
  // set the default for the first parent
  if (arg(2) == 'level1' && !arg(3)) {
    $router .= '/level2';
    $active = TRUE; // quick fix for the first default set active
    return FALSE;
  }
 
  if (arg(3) == 'level3' && !arg(4)) {
    $active = TRUE;
  }
 
  if (!arg(4)) {
    $active = TRUE; // quick fix for the first second level default set active
  }
  // Get all the third tabs
  $result = db_query("SELECT * FROM {menu_router} WHERE tab_parent = '%s' ORDER BY weight, title", $router);
  $map = arg();
  $current_last_path = array_pop($map);
 
  // build the third tabs
  $output = '';
  $tabitem = '';
  while ($item = db_fetch_array($result)) {
    $default_active = FALSE;
    _menu_translate($item, $map, TRUE);
    $linkcheck = explode('/', $item['href']);
 
    $item['localized_options'] = array();
 
    // build the query if there is any
    if (is_numeric($_REQUEST['job'])) {
      $item['localized_options']['query'] = array('job' => $_REQUEST['job']);
    }
 
    if ($active) {
      $item['localized_options']['attributes'] = array('class' => 'active');
      $default_active = TRUE;
      // reset the $active trap since it can only be used once
      $active = FALSE;
    }
    $current_url = array_pop($linkcheck);
    if ($current_url == $current_last_path) {
      $default_active = TRUE;
    }
    $link = theme('menu_item_link', $item);
 
    $tabitem .= theme('menu_local_task', $link, $default_active);
  }
  if (!empty($tabitem)) {
    $output = '<ul class="whateverclass">' . $tabitem . '</ul>';
  }
  return $output;
}