}
public static ChangeInfo deleteHSSFColumns(Worksheet sheet, int startCol, int num) {
final Book book = (Book) sheet.getWorkbook();
final RefSheet refSheet = getRefSheet(book, sheet);
final Set<Ref>[] refs = refSheet.deleteColumns(startCol, num);
final int startCol0 = startCol + num;
final List<CellRangeAddress[]> shiftedRanges = ((HSSFSheetImpl)sheet).shiftColumnsOnly(startCol0, -1, -num, true, false, true, true, Range.FORMAT_NONE);
final List<MergeChange> changeMerges = prepareChangeMerges(refSheet, shiftedRanges);
final Set<Ref> last = refs[0];
final Set<Ref> all = refs[1];