anchor.diff:                     callee_pids => Pids
                      },
         case erwa_invocation_sup:start_invocation(CallInfo) of
  -        {ok, _ } ->
  -          ok;
  +        {ok,Pid} ->
  +          {ok,Pid};
           _ -> {error,invocation_failed}
         end;
       [] ->
  
positive.code:   A = gen_id(),
    B = gen_id(),
    C = A+B,
    ok = erwa_dealer:call(<<"proc.sum">>, RequestId, [], [A,B], undefined,Data),
    ok = receive
           {erwa,{result, RequestId, [], [C], undefined}} -> ok
         end,
  
negative.code: 
  -spec call(Uri :: binary(), RequestId :: non_neg_integer(), Options :: list(),
             Arguments :: list(), ArgumentsKw :: list(), Data :: #data{}) ->
    {ok, pid()} | {error,invocation_failed} | {error, procedure_not_found}.
  call(Uri, RequestId, Options, Arguments, ArgumentsKw, #data{ets=Ets}) ->
    case ets:lookup(Ets,Uri) of
      [#procedure{uri=Uri,pids=Pids,id=ID}] ->
  