anchor.diff:  %% @end 
   %%--------------------------------------------------------------------
   start_link(_) ->
  -    gen_server:start_link({global, {node(), mediator}}, ?MODULE, [], []).
  +  gen_server:start_link({local, mediator}, ?MODULE, [], []).
   
  -join(Node) -> {}.
  +get(Key) -> 
  +  gen_server:call(mediator, {get, Key}).
   
  -get(Key) -> {}.
  +put(Key, Value) -> 
  +  gen_server:call(mediator, {put, Key, Value}).
   
  -put(Key, Value) -> {}.
  +has_key(Key) -> 
  +  gen_server:call(mediator, {has_key, Key}).
  +
  +delete(Key) ->
  +  gen_server:call(mediator, {delete, Key}).
   
   
   
  
positive.code: -behaviour(gen_server).
  
  %% API
  -export([start_link/1, join/1, get/1, put/2]).
  
  %% gen_server callbacks
  -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
  
negative.code: %%--------------------------------------------------------------------
  
  internal_put(Key, Value, #mediator{n=N}) ->
    Servers = membership:server_for_key(Key, N),
    MapFun = fun(Server) ->
      storage_server:put(Server, Key, Value)
    end,
    lib_misc:pmap(MapFun, Servers, []),
    ok.
    
  internal_get(Key, #mediator{n=N}) ->
    Servers = membership:server_for_key(Key, N),
    MapFun = fun(Server) ->
      storage_server:get(Server, Key)
    end,
    Responses = lib_misc:pmap(MapFun, Servers, []),
    [{ok,Value}|_] = lists:filter(fun(Resp) -> {ok,_} = Resp end, Responses),
    Value.
    
  internal_has_key(Key, #mediator{n=N}) ->
    Servers = membership:server_for_key(Key, N),
    MapFun = fun(Server) ->
      storage_server:has_key(Server, Key)
    end,
    Responses = lib_misc:pmap(MapFun, Servers, []),
    [{ok,Value}|_] = lists:filter(fun(Resp) -> {ok,_} = Resp end, Responses),
    Value.
    
  internal_delete(Key, #mediator{n=N}) ->
    Servers = membership:server_for_key(key, N),
    MapFun = fun(Server) ->
      storage_server:delete(Server, Key)
    end,
    Responses = lib_misc:pmap(MapFun, Servers, []),
    [ok|_] = lists:filter(fun(Resp) -> ok = Resp end, Responses),
    ok.