code: function(fn) {
          var me = this;
          fn = fn || me.sorterFn || me.defaultSorterFn;
          me.sort = me.createSortFunction(fn);
      }
docs: Update the sort function for this sorter.
  @param {Function} [fn] A new sorter function for this sorter. If not specified it will use the default
  sorting function.