Since all of these data structures are not Python objects, but stored in the C++ engine, it's not currently possible for you to pickle them. Due to this complexity, there are no plans to expose the functionality of pickling these data structures through the standard Python pickle package.
A fairly simple workaround is to save these objects to the filesystem, and keep pointers to the paths within your class that contains these. On init, your class can simply load from the file paths.
This won't help you when writing classes derived from these objects though. We didn't design these data structures to be extended in this way, and this is the first instance I've heard of someone trying to do this. So if you don't mind, I'd be interested to hear the use case for why you are interested in this.