It converts all uppercase characters to lowercase and vice versa. def makeGood(s): stack=[] for i in s: if stack and stack[-1]!=i and stack[-1].lower()==i.lower(): stack.pop() else: stack.append(i) return ''.join(stack) s='leEeetcode' makeGood(s) >>> 'leetcode' ### IS SAME AS BELOW def makeGood(s): stack=[] for i in s: if stack and stack[-1]==i.swapcase(): stack.pop() else: stack.append(i) retur..