Create a data tree with Python node

I was wondering if somebody could show me a simple example of how a data tree can be created in Python node, and “populated” with some sort of data.
By “data trees” I am thinking of the same principle which Rhino Grasshopper currently uses to store its data.

Thank you in advance.

Maybe I said it in a wrong way.

This is what I meant by a “data tree”:

dynamo_data_tree Are these simple python list of lists? If they are is it possible to manipulate with their indices?

Thank you.