class BlockchainPersistenceUnit extends AbstractPersistenceUnit<K, V> {

    @Override
    public void put(byte[] key, byte[] val) {
        Util.check(key!=null, "key!=null");
        Util.check(val!=null, "val!=null");
        database.put(key, val);
    }

      BlockchainPersistenceUnit(String databasePath, Class<V> clazz);

}