手动实现deepcopy

深拷贝是将对象全拷贝，包括嵌套对象

def deepcopy(cls):
    if isinstance(cls, dict):
        dct = {}
        for k, v in cls.items():
            dct[k] = deepcopy(v)
        return dct

    elif isinstance(cls, list or type):
        li = []
        for index, item in enumerate(cls):
            li.append(deepcopy(item))
        return li
    else:
        return cls