docs: function (array, items, fnEqual) {
          
          if (   !(array instanceof Array)
              || !(items instanceof Array) )
              throw "IllegalArgumentException: expected two Array arguments.";
          
          var isMod = false;
          for (var i = 0, len = items.length; i < len; i++) {
              if (Arrays.addIfMissing(items[i], array, fnEqual))
                  isMod = true;
          }
          
          return isMod;
      }