in src/Sunburst.ts [329:341]
    public enumerateObjectInstances(options: EnumerateVisualObjectInstancesOptions): VisualObjectInstanceEnumeration {
        const instanceEnumeration: VisualObjectInstanceEnumeration = SunburstSettings.enumerateObjectInstances(
            this.settings || SunburstSettings.getDefault(),
            options
        );
        if (options.objectName === Sunburst.LegendPropertyIdentifier.objectName) {
            const topCategories: SunburstDataPoint[] = this.data.root.children;
            this.enumerateColors(topCategories, instanceEnumeration);
        }
        return (<VisualObjectInstanceEnumerationObject>instanceEnumeration).instances || [];
    }