@Brian729 You need one additional level of nesting.
ring2 = [uni_1, uni_2, ...]
ring1 = [uni_1]
level_1 = [ring2, ring1] # 1st axial layer
level_2 = [ring2, ring1] # 2nd axial layer
...
...
...
For more information, see this post; hopefully, you’ll find your answer there.