Proper Parenthetics

proper_parenthetics.py

def is_valid(string):
    if (len(string)) % 2 != 0:
        return False
    braces = {'[':']', '{': '}', '(': ')'}
    opening_braces = braces.keys()
    stack = []
    for char in string:
        if char in opening_braces:
            stack.append(char)
        else:
            is_stack_empty = len(stack) == 0
            if is_stack_empty or braces.get(stack.pop(), None) != char:
                return False
    return len(stack) == 0
            

def main():
    result = is_valid('{[({})]}')
    print(result)
    

if __name__ == "__main__":
    main()