anchor.diff:      link(whereis(?MODULE)),
       put('$ancestors', [?MODULE | get('$ancestors')]).
   
  -add_subscription(Queue, DeliveryProc) ->
  -    add_subscription(Queue, undefined, DeliveryProc).
  -
   add_subscription(Queue, Id, DeliveryProc) ->
       case ets:match_object(?MODULE, {self(), Queue, Id, DeliveryProc}) of
           [] ->
  
positive.code: 
  -export([start_link/0,
           link/0,
           add_subscription/2,
           add_subscription/3,
           del_subscription/2,
           del_subscription/3,
           get_subscriptions/1]).
  
  
negative.code:         [_] ->
              false
      end.
  
  del_subscription(Queue, Id, DeliveryProc) ->
      case ets:match_object(?MODULE, {self(), Queue, Id, DeliveryProc}) of
  