How to turn this into a recursive method?(Python)

In general, to find the k-subsets of set S:

Remove an arbitrary element x S. S is now smaller by one element.

Consider the k-subsets that do contain x: find all (k 1)-subsets of S, and insert x into each of those subsets.

Consider the k-subsets that dont contain x: find all k-subsets of S.

Combine the k-subsets from above to get the answer.

def k_subsets_better(S,k): if k < 0 or k > len(S): return [] subsets = [[]] for i in range(1, len(S) + 1): subsets = power_set(S)

k_subsets = [] for i in subsets: if len(i) == k: k_subsets.append(i)

return k_subsets