/**
  * Clear subscriptions by user
  *
  * @param User $user
  * @return boolean
  */
 static function clearByUser(User $user)
 {
     return ObjectSubscriptions::delete('`user_id` = ' . DB::escape($user->getId()));
 }
 /**
 * Clear subscriptions by user
 *
 * @param Contact $user
 * @return boolean
 */
 static function clearByUser(Contact $user) {
   return ObjectSubscriptions::delete('`contact_id` = ' . DB::escape($user->getId()));
 } // clearByUser