code: func (rq *ResourceQuotaController) syncResourceQuotaFromKey(key string) (err error) {
  	startTime := time.Now()
  	defer func() {
  		klog.V(4).Infof("Finished syncing resource quota %q (%v)", key, time.Since(startTime))
  	}()
  
  	namespace, name, err := cache.SplitMetaNamespaceKey(key)
  	if err != nil {
  		return err
  	}
  	quota, err := rq.rqLister.ResourceQuotas(namespace).Get(name)
  	if errors.IsNotFound(err) {
  		klog.Infof("Resource quota has been deleted %v", key)
  		return nil
  	}
  	if err != nil {
  		klog.Infof("Unable to retrieve resource quota %v from store: %v", key, err)
  		return err
  	}
  	return rq.syncResourceQuota(quota)
  }
docs: // syncResourceQuotaFromKey syncs a quota key