public function display($clear_assign = true)
 {
     $this->view->cache($this->cache_time);
     if ($this->cache_time && $this->isCached()) {
         return $this->view->fetch($this->getTemplate(), $this->cache_id);
     } else {
         if (!$this->cache_time && $this->cache_id) {
             $this->view->clearCache($this->getTemplate(), $this->cache_id);
         }
         $this->execute();
         $result = $this->view->fetch($this->getTemplate(), $this->cache_id);
         if ($clear_assign) {
             $this->view->clearAllAssign();
         }
         return $result;
     }
 }