OfficeBodyElement body = contentDom.newOdfElement(OfficeBodyElement.class);
content.appendChild(body);
ChartChartElement chart = contentDom.newOdfElement(ChartChartElement.class);
//create children element
ChartPlotAreaElement plotArea = chart.newChartPlotAreaElement();
body.appendChild(chart);
p0.getParentNode().insertBefore(content, p0);
XPath xpath = contentDom.getXPath();
ChartChartElement chartTest = (ChartChartElement) xpath.evaluate("//chart:chart[last()]", contentDom, XPathConstants.NODE);