public function off($event)
   {
      list($type, $namespace) = Event::split($event);

      for ($i=count($this->eventHandlers)-1; $i>-1; $i--) {
         $h = $this->eventHandlers[$i];
         if ($type !== null && $h->getType() !== $type) {
            continue;
         }
         else if ($namespace !== null && $h->getNamespace() !== $namespace) {
            continue;
         }
         
         array_splice($this->eventHandlers, $i, 1);
      }

      return $this;
   }