code: func (c Client) DeleteNotificationsOld(age int) error {
  	conn := c.Pool.Get()
  	defer conn.Close()
  
  	currentTime := db.MakeTimestamp()
  	end := int64(int(currentTime) - age)
  
  	objects, err := getObjectsByScore(conn, db.Notification+":modified", 0, end, 0)
  
  	for _, object := range objects {
  		if len(object) > 0 {
  			var n contract.Notification
  			err := unmarshalObject(object, &n)
  			if err != nil {
  				return err
  			}
  			// Delete processed notification
  			if n.Status != contract.Processed {
  				continue
  			}
  			err = deleteNotification(conn, n.ID)
  			if err != nil {
  				return err
  			}
  		}
  	}
  	return err
  }
docs: // DeleteNotificationsOld remove all the notifications that are older than the given age