def _raise_invalid_gzip_err(self):
        """ A gzip file with multiple ARC/WARC records, non-chunked
        has been detected. This is not valid for replay, so notify user
        """
        frmt = 'warc/arc'
        if self.known_format:
            frmt = self.known_format

        frmt_up = frmt.upper()

        msg = self.GZIP_ERR_MSG.format(frmt, frmt_up)
        raise ArchiveLoadFailed(msg)
A gzip file with multiple ARC/WARC records, non-chunked
        has been detected. This is not valid for replay, so notify user