import numbers
class Group:
    #支持切片操作
    def __init__(self, group_name, company_name, staffs):
        self.group_name = group_name
        self.company_name = company_name
        self.staffs = staffs

    def __reversed__(self):   # 魔法函數(shù)，反轉(zhuǎn)，外部可以通過(guò)reversed方法對(duì)此對(duì)象進(jìn)行操作
        self.staffs.reverse()

    def __getitem__(self, item):  # 魔法函數(shù) 切片，外部可以通過(guò)切片的方法對(duì)此對(duì)象進(jìn)行操作
        cls = type(self)
        if isinstance(item, slice):
            return cls(group_name=self.group_name, company_name=self.company_name, staffs=self.staffs[item])
        elif isinstance(item, numbers.Integral):
            return cls(group_name=self.group_name, company_name=self.company_name, staffs=[self.staffs[item]])

    def __len__(self):  # 魔法函數(shù) len，外部可以通過(guò)len計(jì)算此對(duì)象
        return len(self.staffs)

    def __iter__(self):  # 讓此對(duì)象 可以被迭代
        return iter(self.staffs)

    def __contains__(self, item):  # 可以通過(guò)if in 判斷對(duì)象是否包含xxx
        if item in self.staffs:
            return True
        else:
            return False

staffs = ["bobby1", "imooc", "bobby2", "bobby3"]
group = Group(company_name="imooc", group_name="user", staffs=staffs)
reversed(group)
for user in group:
    print(user)