Worth being aware that deeply nested trees are quite inefficient on modern hardware, where CPUs can execute many instructions in the time it takes for a single cache miss. There are techniques to ameliorate this somewhat, e.g. B-trees, but from a quick skim of pygtree it looks like it doesn't use them. You may get a spaghetti of nodes and pointers spread unpredictably over the heap.

It's easy to end up writing code that's got good algorithmic time complexity, but where the CPU spends its time sitting cold and waiting on RAM.