src/org/tiefaces/components/websheet/chart/objects/PieChart.java
@Override
	public final List<CTDPt> getDPtListFromCTSer(final Object ctObjSer) {
		if (ctObjSer instanceof CTPieSer) {
			List<CTDPt> dptList = ((CTPieSer) ctObjSer).getDPtList();
			if (dptList == null) {
				// return empty list instead of null for pie.
				// this will ensure pie create valueColorList in serial object.
				dptList = new ArrayList<>();
			}
			return dptList;
		}
		return this.getEmptyDptlist();
	}
@Override
	public final List<CTDPt> getDPtListFromCTSer(final Object ctObjSer) {
		if (ctObjSer instanceof CTPieSer) {
			List<CTDPt> dptList = ((CTPieSer) ctObjSer).getDPtList();
			if (dptList == null) {
				// return empty list instead of null for pie.
				// this will ensure pie create valueColorList in serial object.
				dptList = new ArrayList<>();
			}
			return dptList;
		}
		return this.getEmptyDptlist();
	}
/*
(non-Javadoc)

@see org.tiefaces.components.websheet.chart.objects.ChartObject#
getDPtListFromCTSer(java.lang.Object)