public void storeFlattened(final OutputStream out) throws IOException {
    final Properties p = new Properties();
    for (Props curr = this; curr != null; curr = curr.getParent()) {
      for (final String key : curr.localKeySet()) {
        if (!p.containsKey(key)) {
          p.setProperty(key, get(key));
        }
      }
    }

    p.store(out, null);
  }
Store all properties, those local and also those in parent props

@param out The stream to write to
@throws IOException If there is an error writing
dss-appconn/appconns/dss-eventchecker-appconn/src/main/java/com/webank/wedatasphere/dss/appconn/eventchecker/utils/Props.java