deque in Python

stack.py

from collections import deque


class Solution:
    def isValid(self, s: str) -> bool:
        mapping = {')': '(', ']': '[', '}': '{'}
        stack = deque()
        for char in s:
            if mapping.get(char):
                if len(stack) == 0:
                    return False
                else:
                    if stack.pop() != mapping[char]:
                        return False
            else:
                stack.append(char)
        return not stack