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.

Write a Python function k subsets better(S, k) that uses the recursive algorithm presented above to return a set containing all the k-subsets of S. As before, represent the sets using Python lists. If k is not valid (i.e., negative, or greater than |S|), this function should return the empty list, [].