docs: def to_xlsx(self, **kwargs):
          """
          Write workbook to a .xlsx file using xlsxwriter.
          Return a xlsxwriter.workbook.Workbook.
  
          :param kwargs: Extra arguments passed to the xlsxwriter.Workbook
          constructor.
          """
          from xlsxwriter.workbook import Workbook as _Workbook
          self.workbook_obj = _Workbook(**kwargs)
          self.workbook_obj.set_calc_mode(self.calc_mode)
  
          for worksheet in self.itersheets():
              worksheet.to_xlsx(workbook=self)
  
          self.workbook_obj.filename = self.filename
          if self.filename:
              self.workbook_obj.close()
          return self.workbook_obj