How to make a nested dictionary and dynamically append data

Question

I have a loop giving me three variables

matteGroup
matteName
object

I would like to make a nested dicionary holding all the data like:

Answer 1

Due to an issue with pickling my object, that used some of the previous answers, I tried to solve this as well. This is what worked for me for dynamically adding new keys to two different sub levels of dictionaries:

from collections import defaultdict
test = defaultdict(defaultdict)
test["level1"]["level2"] = 1
test["level1"]["level2_second"] = 2
print(test)

defaultdict(, {'level1': defaultdict(None, {'level2': 1, 'level2_second': 2})})

This solution seems to be only able to handle two levels of nesting.