docs: function srandmember(key /* count, 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) {
      return args[0] === undefined ? null : [];
    }
    return val.srandmember(args[0]);
  }