docs: function() {
      new Function(arguments[arguments.length - 3]).apply(null,
          (function(args) {
            var realCallback = args[args.length - 1];
            var unwrapperCallback = args[args.length - 2];
            Array.prototype.splice.apply(args, [args.length - 3, 3]);
            args.push(function(result) {
              unwrapperCallback(result, realCallback);
            });
            return args;
          })(Array.prototype.slice.apply(arguments, [0])));
    }