anchor.diff:  -spec init_per_round(atom(), [binary()], [pos_integer()]) -> ok.
   init_per_round(Fun, Keys, [Port]) when Fun =:= zcard;
                                          Fun =:= zadd_one;
  -                                       Fun =:= zcount_n;
                                          Fun =:= zincrby;
  -                                       Fun =:= zrange_n;
  -                                       Fun =:= zrangebyscore_n;
                                          Fun =:= zremrangebyrank_n;
  -                                       Fun =:= zremrangebyscore_n;
  -                                       Fun =:= zrevrange_n;
  -                                       Fun =:= zrevrangebyscore_n ->
  +                                       Fun =:= zrevrange_n ->
     zadd(Keys, Port),
     ok;
   init_per_round(Fun, Keys, [Port]) when Fun =:= zinterstore_min ->
  
positive.code:   erldis:zadd(process(Port), ?KEY,
                [{1.0 * I, edis_util:integer_to_binary(I)} || I <- lists:seq(1, 10000)]),
    ok;
  init_per_round(Fun, Keys, [Port]) when Fun =:= zrank;
                                         Fun =:= zrevrank;
                                         Fun =:= zrem_one;
                                         Fun =:= zscore ->
    erldis:zadd(process(Port), ?KEY, [{edis_util:binary_to_float(Key), Key} || Key <- Keys]),
  
negative.code: 
  -spec zrevrangebyscore_n([binary()], pos_integer()) -> [binary()].
  zrevrangebyscore_n(_Keys, Port) ->
    erldis:zrevrangebyscore(process(Port), ?KEY, 1.0, <<"-inf">>).
  
  -spec zrevrangebyscore_m([binary()], pos_integer()) -> [binary()].
  zrevrangebyscore_m([Key|_], Port) ->
    erldis:zrevrangebyscore(process(Port), ?KEY, edis_util:binary_to_float(Key), <<"-inf">>).
  
  -spec zrevrank([binary()], pos_integer()) -> number().
  zrevrank(_Keys, Port) ->
  