def METHOD_NAME(self, n_bytes):
    """update Update the total number of bytes.
    Args:
        n_bytes (int): Total number of bytes processed so far.
    """
    if self._total_size is None:
        raise RuntimeError('progress not configured with "bytes" value')
    pct = float(n_bytes)/self._total_size
    return self.update_percent(pct, ratio=[n_bytes, self._total_size])