anchor.diff:  
   -module(manager).
   -export(loop/1).
  +
  +notify_subscriber(Subscriber, Data) ->
  +	case is_pid(Subscriber) of
  +		true ->
  +			Subscriber ! Data
  +	end.
   
   %%----------------------------------------------------------------------
   %% Function: loop/1
  
positive.code: 		% called when the subscriber wants to refresh their downloads
  		%%
  		{subscriber_refresh, Subscriber} ->
  			Subscriber ! {downloads, Downloads},
  			loop(Account, Downloads, Subscriber);
  
  		%%
  
negative.code: 			UpdatedDownload = Download::set(status, ?DL_COMPLETE),
  			case UpdatedDownload::save() of
  				{ok, SavedDownload} ->
  					notify_subscriber(Subscriber, {on_download_complete, [{download, Download}]});
  				{error, Errors} ->
  					notify_subscriber(Subscriber, {on_download_error, [{download, Download}, {errors, Errors}]})
  			end,
  			loop(Account, Downloads, Subscriber)
  			
  