anchor.diff:        'B2': {'C1': 7, 'C2': 8}
       },
     };
  -  List res = flattenMap(data);
  -  //res.forEach(print);
     test('flattenMap, three nesting levels', () {
  +    List res = flattenMap(data, ['level0', 'level1', 'level2', 'value']);
       expect(res, [
         {'value': 1, 'level2': 'C1', 'level1': 'B1', 'level0': 'A1'},
         {'value': 2, 'level2': 'C2', 'level1': 'B1', 'level0': 'A1'},
  
positive.code:     'B2': {'Jan15': 3, 'Feb15': 4},
      'B3': {'Jan15': 5, 'Feb15': 6}
    };
    List res = flattenMap(data);
    //res.forEach(print);
    test('flattenMap, two nesting levels', () {
      expect(res, [
        {'level0': 'B1', 'level1': 'Jan15', 'value': 1},
        {'level0': 'B1', 'level1': 'Feb15', 'value': 2},
  
negative.code: 
  test1() {
    Map data = {'A': 10, 'B': 20, 'C': 30};
    List res = flattenMap(data, ['level0', 'value']);
    //res.forEach(print);
    test('flattenMap, one nesting level', () {
      expect(res, [
  