python - 可调用的迭代器大小？

my_list = [1, 2, 3, 4, 5]
print(len(my_list))  # 输出：5

my_tuple = (1, 2, 3, 4, 5)
print(len(my_tuple))  # 输出：5

my_string = "Hello, world!"
print(len(my_string))  # 输出：13

class MyIterable:
    def __init__(self, data):
        self.data = data

    def __iter__(self):
        return iter(self.data)

    def __len__(self):
        return len(self.data)

my_iterable = MyIterable([1, 2, 3, 4, 5])
print(len(my_iterable))  # 输出：5