如何克隆迭代器？

class CloneableIterator:
    def __init__(self, iterable):
        self._iterable = iterable
        self._iterator = iter(iterable)

    def __iter__(self):
        return self

    def __next__(self):
        return next(self._iterator)

    def clone(self):
        return CloneableIterator(self._iterable)

# 示例
iterable = [1, 2, 3, 4, 5]
iterator1 = CloneableIterator(iterable)
iterator2 = iterator1.clone()

print(next(iterator1))  # 输出：1
print(next(iterator2))  # 输出：1
print(next(iterator1))  # 输出：2
print(next(iterator2))  # 输出：2