How to use the b2sdk.utils.format_and_scale_fraction function in b2sdk

def _check_one(self, expected, numerator, denominator):
        self.assertEqual(
            expected, b2sdk.utils.format_and_scale_fraction(numerator, denominator, 'B')
        )

)  # yapf: disable
                elif not self.compare_done:
                    message = ' compare: %d/%d files   updated: %d files   %s   %s' % (
                        self.compare_count,
                        self.local_file_count,
                        self.transfer_files,
                        format_and_scale_number(self.transfer_bytes, 'B'),
                        format_and_scale_number(rate, 'B/s')
                    )  # yapf: disable
                else:
                    message = ' compare: %d/%d files   updated: %d/%d files   %s   %s' % (
                        self.compare_count,
                        self.local_file_count,
                        self.transfer_files,
                        self.total_transfer_files,
                        format_and_scale_fraction(self.transfer_bytes, self.total_transfer_bytes, 'B'),
                        format_and_scale_number(rate, 'B/s')
                    )  # yapf: disable
                self._print_line(message, False)