function access($op, $item) {
   $access = parent::access($op, $item);
   if ($op == 'add' && $access && empty($this->base_types)) {
    // Make sure there are base styles defined.
    $access = FALSE;
   }
   return $access;
 }
 function access($op, $item)
 {
     $access = parent::access($op, $item);
     if ($op == 'add' & $access && empty($this->base_types)) {
         // Make sure there are base styles defined.
         $access = FALSE;
         // Give a warning about the missing base styles.
         drupal_set_message($this->plugin['strings']['message']['missing base type'], 'warning');
     }
     return $access;
 }