anchor.diff:                      %% Increment it.
                       {ok, _} = lasp:update(Ad, increment, Id),
   
  -                    client(Id, AdsWithContracts, AdList0)
  +                    client(Runner, Id, AdsWithContracts, AdList0)
               end
       end.
   
   %% @doc Simulate clients viewing advertisements.
  -simulate(ClientList) ->
  +simulate(_Runner, ClientList) ->
       %% Start the simulation.
       Viewer = fun(_) ->
               Random = random:uniform(length(ClientList)),
  
positive.code:     ok = lasp:filter(AdsContracts, FilterFun, AdsWithContracts),
  
      %% Launch client processes.
      ClientList = clients(AdsWithContracts),
  
      %% Launch server processes.
      servers(Ads, AdsWithContracts),
  
      %% Initialize simulation.
      simulate(ClientList),
  
      %% Finish and summarize.
      summarize(AdsWithContracts),
  
negative.code:                 0 ->
                      %% No advertisements left to display; ignore
                      %% message.
                      client(Runner, Id, AdsWithContracts, AdList0);
                  _ ->
                      %% Select a random advertisement from the list of
                      %% active advertisements.
  