anchor.diff:  
         for (final category in singleCategoryModel.categories) {
           seriesData.add(new ChartInnerDataSets(
  -          name: category,
  +          name: category.toString(),
             y: singleCategoryModel.getValue(category),
             color: singleCategoryModel.getValueColor(category),
             visible: singleCategoryModel.getValueColor(category) != null));
  
positive.code:   static final String line = 'line';
  }
  
  abstract class Chart<T extends ChartModel> {
  
    Element get element;
  
  
negative.code:       data[series] = values;
      }
  
      for (S series in data.keys)
        list.add(new ChartDataSets(
          name: series.toString(),
          color: model.getSeriesStyle(series, SeriesStyle.color),
          borderRadius: model.getSeriesStyle(series, SeriesStyle.borderRadius),
          fillOpacity: model.getSeriesStyle(series, SeriesStyle.fillOpacity),
  