How to do balanced parentheses?

Question

I tried this - worked on all the test cases but test 3 which is hidden - thanks in advance

def balanced(expression):
#your code goes here
stack = []
for b in expression:
if b == "(":
stack.insert(0, b)
if b == ")" and len(stack) > 0:
stack.pop()
return len(stack) == 0

print(balanced(input()))

Answer 1

If for ex: input is ) or
)() return true but it shoud be false

Answer 2

Thank you!

Answer 3

someone give me the answer please?