* @throws DmcValueExceptionSet
*/
void addExtendedReferenceType(ExtendedReferenceTypeDefinition ertd) throws ResultException, DmcValueException {
if (checkAndAdd(ertd.getObjectName(),ertd,extendedReferenceTypeDefs) == false){
ResultException ex = new ResultException();
ex.addError(clashMsg(ertd.getObjectName(),ertd,extendedReferenceTypeDefs,"extended reference type names"));
throw(ex);
}
TypeDefinition td = new TypeDefinition();
td.setInternallyGenerated(true);