anchor.diff:  
   prop_limit_ok() ->
       ?FORALL(
  -       MaxSize, c_size(),
  -       ?FORALL(Cache, cache(MaxSize),
  +       {MaxSize, Opts}, {c_size(), opts()},
  +       ?FORALL(Cache, cache(MaxSize, Opts),
                  begin
                      %% io:format("~p~n", [Cache]),
                      {H, _, _} = eval(Cache),
  
positive.code: v_time() ->
      nat().
  
  cache(MaxSize, 0) ->
      {call, ?MODULE, new, [MaxSize]};
  
  cache(MaxSize, Size) ->
      ?LAZY(
         ?LETSHRINK(
            [H], [cache(MaxSize, Size -1)],
            frequency(
              [
               {1,   {call, ?MODULE, age, [H]}},
  
negative.code:       N, fun(Acc) -> maps:put(O, V, Acc) end,
        maps:from_list([{O, V}]), T).
  
  new(Size, Opts) ->
      {ok, H} = mcache:new(Size, Opts),
      {H, #{}, []}.
  
  insert({H, T, Ds}, N, O, V) ->
  