parens.py

opposites = {
    ")": "(",
    "]": "[",
    "}": "{",
}


def check(s):
    stack = []
    for c in s:
        if c in ")}]":
            if stack.pop() != opposites[c]:
                return False
        else:
            stack.append(c)
    return len(stack) == 0


def braces(values):
    res = []
    for x in values:
        if check(x):
            res.append("yes")
        else:
            res.append("no")
    return res