public static GsonBuilder createGsonBuilder() {
GsonBuilder builder = new GsonBuilder();
// uncomment if you wish to debug generated json
builder.setPrettyPrinting();
builder.registerTypeHierarchyAdapter(ChartEnum.class,
new ChartEnumSerializer());
builder.registerTypeHierarchyAdapter(SolidColor.class,
new SolidColorSerializer());
builder.registerTypeHierarchyAdapter(AxisList.class,
new AxisListSerializer());
builder.registerTypeHierarchyAdapter(PaneList.class,