#!/usr/bin/python
class MyRange:
    def __init__(self, m = 0):
        self.max = m
        self.n = 0
 
    def __iter__(self):
        print('Call __iter__ ...')
        self.n = 0
        return self
 
    def next(self):
        print('Call __next__ ...')
        if self.n <= self.max:
            result = 2 ** self.n
            self.n += 1
            return result
        else:
            raise StopIteration
 
def main():
    l = iter(MyRange(4)) # __iter__
    while True:
        try:
            print(l.next()) # next
        except StopIteration, err:
            print(err)
            break
 
if __name__ == '__main__':
    main();
	
		

#!/usr/bin/python
class MyRange:
    def __init__(self, m = 0):
        self.max = m
        self.n = 0

    def __iter__(self):
        print('Call __iter__ ...')
        self.n = 0
        return self

    def __next__(self):
        print('Call __next__ ...')
        if self.n <= self.max:
            result = 2 ** self.n
            self.n += 1
            return result
        else:
            raise StopIteration('End of iteration ...')
 
def main():
    l = iter(MyRange(4))
    while True:
        try:
            print(next(l))
        except StopIteration as err:
            print(err)
            break

if __name__ == '__main__':
    main();