@Override
    public Storeable put(final String keyStr, final Storeable storeableValue) {
        checkKey(keyStr);
        if (storeableValue == null) {
            throw new IllegalArgumentException("Wrong put value = null!");
        }
        DirFile node = new DirFile(keyStr.getBytes()[0]);
        DataBaseFile file = files[node.getId()];
        String value = WorkWithJSON.serialize(this, storeableValue);

        String result;
        result = file.put(keyStr, value);
        return WorkWithJSON.deserialize(this, result);
    }