docs: function srem(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) return 0;
    var deleted = val.srem(args);
    if(val.scard() === 0) {
      this.delKey(key, req);
    }
    return deleted;
  }