def check_against_chunks(self, chunks):
        # type: (Iterator[bytes]) -> None
        """Check good hashes against ones built from iterable of chunks of
        data.

        Raise HashMismatch if none match.

        """
        gots = {}
        for hash_name in iterkeys(self._allowed):
            try:
                gots[hash_name] = hashlib.new(hash_name)
            except (ValueError, TypeError):
                raise InstallationError('Unknown hash name: %s' % hash_name)

        for chunk in chunks:
            for hash in itervalues(gots):
                hash.update(chunk)

        for hash_name, got in iteritems(gots):
            if got.hexdigest() in self._allowed[hash_name]:
                return
        self._raise(gots)
Check good hashes against ones built from iterable of chunks of
        data.

        Raise HashMismatch if none match.