code: function (err, data, next) {
        var args = [err];
        if (err) { args.push(undefined); }
        else if (! err) { args.push(data); }
        next.apply(this, args);
      }
docs: Internal helper function used to pass ``err``, ``data`` to ``next``. Just some centralized boilerplate that provides the following features: - ensures ``err``, ``data`` always present - passed undefined instead of ``data`` if ``err`` is present - invokes ``next`` callback in context of ``this``