Description Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same type of brackets. Open brackets must be closed in the correct order. My solution class Solution: def isValid(self, s: str) -> bool: stack = [] for i in s: if i in ('(', '[', '{'): stack.append(i)..