iter_next.py

'''
    How to declare a iterator on any kind of object
'''
class PowersOfTwo:
    def __init__(self, max=0):
        self.max = max

    def __iter__(self):
        self.n = 0
        return self

    def __next__(self):
        if self.n <= self.max:
            result = 2 ** self.n
            self.n += 1
            return result
        else:
            raise StopIteration

powers = PowersOfTwo(4)
for power in powers:
    print(power)