Valid Parentheses

def isValid(s) :
        stack = []
        
        for i in s:
            t= True
            if i=="(" or i=="{" or i=="[":
                stack.append(i)
            elif i==')' and stack[-1]=="(":
                stack.pop()
            elif i=='}' and stack[-1]=="{":
                stack.pop()
            elif i==']' and stack[-1]=="[":
                stack.pop()
            else:
                t= False
        return t
        
        
        
        
print(isValid("()"))