anchor.diff:      ?line ok = gen_event:add_sup_handler(my_dummy_handler, dummy_h, [self()]),
       ?line ok = gen_event:sync_notify(my_dummy_handler,
   				     {swap_event,dummy1_h,swap}),
  -    ?t:sleep(1000),
       ?line [dummy1_h] = gen_event:which_handlers(my_dummy_handler),
   
       ?line ok = gen_event:sync_notify(my_dummy_handler, delete_event),
  
positive.code: 		  ok
  	  end,
      ?line my_dummy_handler ! {swap_info,dummy1_h,swap},
      ?t:sleep(1000),
      ?line [dummy1_h] = gen_event:which_handlers(my_dummy_handler),
      ?line my_dummy_handler ! Info,
      ?line receive
  
negative.code: 		  ok
  	  end,
      ?line ok = gen_event:notify(my_dummy_handler, {swap_event,dummy1_h,swap}),
      ?line [dummy1_h] = gen_event:which_handlers(my_dummy_handler),
      ?line ok = gen_event:notify(my_dummy_handler, Event),
      ?line receive
  