anchor.diff:    }
   
     String calPrintMtable(String date, String curdate) {
  -    String output;
  +    String output = "";
       DateTime dartDate = new DateTime(int.parse(date.substring(0, 4)),
           int.parse(date.substring(4, 6)), int.parse(date.substring(6, 8)));
   
  
positive.code:   final _random = new Random();
    int _next(int min, int max) => min + _random.nextInt(max - min);
    List _calWtable = new List();
    List _calMtable = new List();
  
    var _pool;
    final String _calTable = "lwc";
  
negative.code: 
      for (int i = 0, w = 0; i < mdays; i++) {
        if (i != 0 && wd == 0) w++;
        List tmp = [i+1]; //TODO
        _calMtable.insert(w,tmp);
        wd = (wd + 1) % 7;
      }
    }
  