Enable XlsxWriter Worksheet object to be opened, operated on, and
        then automatically closed within a `with` statement. A filename or
        stream object (such as a ``BytesIO`` instance) is expected as
        *xlsx_file*.

def _open_worksheet(self, xlsx_file):
        """
        Enable XlsxWriter Worksheet object to be opened, operated on, and
        then automatically closed within a `with` statement. A filename or
        stream object (such as a ``BytesIO`` instance) is expected as
        *xlsx_file*.
        """
        workbook = Workbook(xlsx_file, {'in_memory': True})
        worksheet = workbook.add_worksheet()
        yield workbook, worksheet
        workbook.close()