如何解决括号匹配问题

# coding:utf-8

def BracketMatch(str):

    #把左括号与右括号分别放在一组

    LeftBrackets  = '{[('

    RightBrackets = '}])'

    #根据括号的匹配关系建立一个字典,右括号当key,左括号当value

    Brackets = {'}':'{',']':'[',')':'('}

    # 建立一个栈，初始值为空列表

    Stack = [ ]

    for char in (str):

        if char in LeftBrackets:

            Stack.append(char)

        if char in RightBrackets:

            if Stack == [ ]:

                return False

            else:

                if Brackets[char] == Stack[-1]:

                    Stack.pop()

                else:

                    return False

    if Stack == [ ]:

        return True

    else:

        return False

str = input('请输入字符：')

print(BracketMatch(str))