@staticmethod
def hint_check_unbalanced_parens(ans, term):
    """
        ans = student answer
        term = ignored
    
        Returns True if parentheses are unbalanced
        """
    stack = []
    pushChars, popChars = '({[', ')}]'
    for c in ans:
        if c in pushChars:
            stack.append(c)
        elif c in popChars:
            if not len(stack):
                return True
            else:
                stackTop = stack.pop()
                balancingBracket = pushChars[popChars.index(c)]
                if stackTop != balancingBracket:
                    return True
    return len(stack) > 0
