Spreadsheet gem errors

I am using the spreadsheet gem to try to create workbook by copying the
first worksheet

work_book = Spreadsheet.open ‘./test.xls’
sheet = work_book.worksheet 0

sheet2 work_book.add_worksheet(sheet)
sheet.name = “copy”


I get a corrupt file with the following with the following log:

Microsoft Office Excel File Repair Log

Errors were detected in file
The following is a list of repairs:

Damage to the file was so extensive that repairs were not possible.
attempted to recover your formulas and values, but some data may have
lost or corrupted.

does the add_worksheet function work and am I using it right?