class Foo(object):
    def __init__(self, data):
        self.data = data

    def __iter__(self):
        for item in self.data:
            yield item

user_list = [
        {'id': 1, 'name': 'alex', 'age': 19},
        {'id': 2, 'name': 'eric', 'age': 18},
    ]
    obj = Foo(user_list)

for i in Foo(user_list ):
        priny(i)

yield會(huì)來(lái)到iter方法