}
protected CTCalcChain getCalculationChain() {
CTCalcChain calculationChain = null;
try {
CalcChain part = (CalcChain) result.getPackage().getParts().get(new PartName("/xl/calcChain.xml"));
if (part != null) {
calculationChain = part.getJaxbElement();
calculationChain.getC().clear();
}
} catch (InvalidFormatException e) {
//do nothing
}