I want to know what does [3, 3, 0, 1][cakes % 4] means??

Not best practice, since it overwrites a built-in.

The kata is written with the variabler lst so this isn't an issue of the kata.

I think the question is a bit misworded. The question should say we are to find the number of subsets from a set, not subsets from a list. If it's the first case, then by definition all elements should be unique.

2^n is correct if you assume unique elements in the list.
I tried 2**(len(set(lst))) as the answer and it didn't like it in the test cases,
so they are assuming each item is unique.