anchor.diff:  
   init(_Args)->
       {ok,[]}.
  -handle_event(send_message,To,Msg)-> 
  +handle_event({send_message,To,Msg},State)-> 
   
       Member = pg2:get_members(To),
   
  
positive.code: 		  {error,_}-> self()!{error,unavailable}
  	      end
        end,
        To);
  
  handle_event(subscribe,To,Channel)->
      
      Member = pg2:get_members(To),
      case Member of
  	[To|_]->pg2:join(Channel),
  		self()!subscribed;
  	{error,_} ->self()!error
      end;
  
  handle_event(subscribe,To,Channels) when is_list(Channels) ->
  
      Member = pg2:get_members(To),
      case Member of
  
negative.code: 		 self()!subscribed;
  	{error,_}-> self()!error
      end;
  {ok,State};
  handle_event({publish,Channel,Msg})->
  
      Member = pg2:get_members(Channel),
      case Member of 
  	[Channel|_]->Channel!{Channel,Msg};
  	{error,_}-> failed
      end
  	{ok,State}.
  