class Blockchain implements Serializable, PersistenceUnitContainer {

    @Override
    public void stopPersistenceUnit() {
        logger.traceEntry();
        for (PersistenceUnit<?, ?> unit : blockchain.values()) {
            try {
                unit.close();
            } catch (IOException e) {
                logger.catching(e);
            }
        }
        logger.traceExit();
    }

    public  Blockchain(BlockchainContext context);

}