anchor.diff:  
       ?line ok = gen_event:add_sup_handler(my_dummy_handler, dummy_h, [self()]),
       ?line ok = gen_event: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:notify(my_dummy_handler, do_crash),
  
positive.code: 	  end,
      ?line ok = gen_event:sync_notify(my_dummy_handler,
  				     {swap_event, {dummy1_h, 9}, swap}),
      ?t:sleep(1000),
      ?line [{dummy1_h,9}] = gen_event:which_handlers(my_dummy_handler),
      ?line ok = gen_event:sync_notify(my_dummy_handler, Event),
      ?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
  