code: function sadd(key /* member-1, member-N, req */) {
    var args = slice.call(arguments, 1)
      , req = typeof args[args.length-1] === 'object' ? args.pop() : null
      , val = this.getKey(key, req);
    if(val === undefined) {
      val = new Set();
      this.setKey(key, val, undefined, undefined, undefined, req);
    }
    return val.sadd(args);
  }
docs: Add the specified members to the set stored at key.