def hexdigest(self):
        """Return the digest value as a string of hexadecimal digits."""
        if not self._final:
            if self._buf_len >= self._MIN_LEN:
                self._tlsh.final()
                self._final = True
            else:
                raise ValueError("tlsh requires buffer with length >= %d "
                                 "for mode where force = %s" % \
                                 (self._MIN_LEN, False))
        return self._tlsh.hexdigest()