public function delete($channel_id, $user_id)
 {
     parent::delete($channel_id, array('id' => $user_id));
 }
 public function delete($user_id, $channel_id)
 {
     parent::delete($user_id, array('id' => $channel_id));
     channel_user_peer::instance()->delete($channel_id, $user_id);
 }