anchor.diff:  
     List<int> sublist(int start, [int end]) {
       if (end == null) end = length;
  -    return Lists.getRange(this, start, end, <int>[]);
  +    return _Lists.getRange(this, start, end, <int>[]);
     }
   
     Map<int, int> asMap() =>
  
positive.code:   }
  
    int indexOf(int element, [int start = 0]) =>
        Lists.indexOf(this, element, start, this.length);
  
    int lastIndexOf(int element, [int start]) {
      if (start == null) start = length - 1;
      return Lists.lastIndexOf(this, element, start);
    }
  
    int get first {
  
negative.code: 
    List<num> sublist(int start, [int end]) {
      if (end == null) end = length;
      return _Lists.getRange(this, start, end, <num>[]);
    }
  
    Map<int, num> asMap() =>
  