code: function reduceRight(collection, callback, accumulator, thisArg) {
        var iterable = collection,
            length = collection ? collection.length : 0,
            noaccum = arguments.length < 3;
  
        if (typeof length != 'number') {
          var props = keys(collection);
          length = props.length;
        }
        callback = lodash.createCallback(callback, thisArg, 4);
        forEach(collection, function(value, index, collection) {
          index = props ? props[--length] : --length;
          accumulator = noaccum
            ? (noaccum = false, iterable[index])
            : callback(accumulator, iterable[index], index, collection);
        });
        return accumulator;
      }
docs: This method is similar to `_.reduce`, except that it iterates over a
  `collection` from right to left.
  
  @static
  @memberOf _
  @alias foldr
  @category Collections
  @param {Array|Object|String} collection The collection to iterate over.
  @param {Function} [callback=identity] The function called per iteration.
  @param {Mixed} [accumulator] Initial value of the accumulator.
  @param {Mixed} [thisArg] The `this` binding of `callback`.
  @returns {Mixed} Returns the accumulated value.
  @example
  
  var list = [[0, 1], [2, 3], [4, 5]];
  var flat = _.reduceRight(list, function(a, b) { return a.concat(b); }, []);
  // => [4, 5, 2, 3, 0, 1]