Python-сообщество

class MyClass:
    def __init__(self):
        self.__items = {}

obj = MyClass()
for item in obj:
    ...

class MyClass(object):
    def __init__(self,  items):
        self.__items = items
    def __iter__(self):
        for i in self.__items:
            yield i

>>> class MyClass:
...     def __init__(self):
...         self.__items = {1: 2, 3: 4}
...     def __iter__(self):
...         return iter(self.__items)
... 
>>> for i in MyClass():
...     print(i)
... 
1
3
>>>