1. Complete the following python code to construct an iterable class
of partitions of n (in pure python):

class Partitions:
    def __init__(self, n):
        self.n = n

    def __iter__(self):
    	return self

    def next(self):

2. Find out why the following sage code does not produce the expected 
reuslt:

sage: for w in Permutations(5):
....:    try:
....:        print w.next().prev() == w
....:    except AttributeError:
....:        pass