Convert batch of FileStoreHashs.

def BatchConvert(self, metadata_value_pairs, token=None):
    """Convert batch of FileStoreHashs."""

    urns = [urn for metadata, urn in metadata_value_pairs]
    urns_dict = dict((urn, metadata) for metadata, urn in metadata_value_pairs)

    results = []
    for hash_urn, client_files in filestore.HashFileStore.GetClientsForHashes(
        urns, token=token):
      for hit in client_files:
        metadata = ExportedMetadata(urns_dict[hash_urn])
        metadata.client_urn = rdfvalue.RDFURN(hit).Split(2)[0]

        result = ExportedFileStoreHash(
            metadata=metadata,
            hash=hash_urn.hash_value,
            fingerprint_type=hash_urn.fingerprint_type,
            hash_type=hash_urn.hash_type,
            target_urn=hit)
        results.append(result)

    return results