class Solution:
    def isValid(self, string: str) -> bool:

            stack = []
            mapping = {
                "}" : "{",
                ")" : "(",
                "]" : "["
            }

            for s in string:
                if s in ["{", "(", "["]:
                    stack.append(s)
                elif s in ["}", ")", "]"]:
                    if len(stack) > 0 and stack[-1] == mapping[s]:
                        stack.pop()
                    else:
                        return False
                else:
                    continue

            # return only if stack is empty
            return (len(stack) == 0)