Dictionary of dictionaries of tensors

Hi!. I want to create a dictionary of dictionaries in which I save some tensors. Imagine I have this dictionary:

data = {‘1’:[], ‘2’:[], ‘3’:[]}

and on each of these instances I have the dictionary {‘x’:[], ‘y’:[], ‘z’:[]}, that is to say

data = {‘1’:{‘x’:[], ‘y’:[], ‘z’:[]}, ‘2’:{‘x’:[], ‘y’:[], ‘z’:[]}, ‘3’:{‘x’:[], ‘y’:[], ‘z’:[]}}

In my case, I have more than just three instances, and inside each of them I have more instances, that’s why I would like to know if there is a better way to define the dictionary data. Thanks in advance!!