682 baseball game

def (self, ops):
    """
    :type ops: List[str]
    :rtype: int
    """
    obj = [0,[]]
    for i in ops:
        if i == "C":
            last = obj[1].pop()
            obj[0] -= last
        elif i == "D":
            obj[1].append(obj[1][-1]*2)
            obj[0] += obj[1][-1]
        elif i == "+":
            obj[1].append(obj[1][-1]+obj[1][-2])
            obj[0]+= obj[1][-1]
        else:
            obj[1].append(int(i))
            obj[0] += obj[1][-1]
    return obj[0]