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: 
  -spec zrevrangebyscore_n([binary()], pos_integer()) -> [binary()].
  zrevrangebyscore_n(_Keys, Port) ->
    erldis:zrevrangebyscore(process(Port), ?KEY, <<"-inf">>, 1.0).
  
  -spec zrevrangebyscore_m([binary()], pos_integer()) -> [binary()].
  zrevrangebyscore_m([Key|_], Port) ->
    erldis:zrevrangebyscore(process(Port), ?KEY, {inc, edis_util:binary_to_float(Key)}, <<"-inf">>).
  
  -spec zrevrank([binary()], pos_integer()) -> number().
  zrevrank(_Keys, Port) ->
  
negative.code:   erldis:zrem(process(Port), ?KEY, Key).
  
  -spec zrem([binary()], pos_integer()) -> pos_integer().
  zrem([Key|_], Port) ->
    erldis:zrem(process(Port), ?KEY, [Key]).
  
  -spec zremrangebyrank_n([binary()], pos_integer()) -> number().
  zremrangebyrank_n(_Keys, Port) ->
  