docs: function nodeify(task) {
      task = promisen(task);
      return nodeifyTask;
  
      function nodeifyTask(args, callback) {
        args = Array.prototype.slice.call(arguments);
        callback = (args[args.length - 1] instanceof Function) && args.pop();
        if (!callback) callback = NOP;
        var onResolve = callback.bind(this, null);
        var onReject = callback.bind(this);
        task.apply(this, args).then(onResolve, onReject);
      }
    }