code: private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
  		in.defaultReadObject();
  		if (this.children != null) {
  			final N me = toN();
  			for (final NaryTreeNode<D, N> child : this.children) {
  				if (child != null) {
  					child.setParentNodeReference(me, false);
  				}
  			}
  		}
  	}
docs: Invoked when this object must be deserialized.
  
  @param in is the input stream.
  @throws IOException in case of input stream access error.
  @throws ClassNotFoundException if some class was not found.