code: function (index, count) {
          validateListIndex(this, index + count - 1);
          return new List(this.slice(index, index + count));
      }
docs: Creates a shallow copy of a range of elements in the source List.
  @param {Number} index The zero-based List index at which the range starts.
  @param {Number} count The number of elements in the range.
  @returns {List}