Codility - Nesting

def solution(S): # write your code in Python 3.6 if len(S) == 0: return 1 if len(S) == 1: return 0 stack = [] for char in S: if char=="(": stack.append(char) else: if len(stack) > 0: stack.pop() else: return 0 if len(stack) > 0: return 0 return 1