Iterator and Generator example

import itertools

def fib(n):
    a, b = 1, 1
    for _ in range(n):
        yield a
        a, b = b, a + b
    return "I'm tired"

class Fib:
    def __init__(self):
        self.a, self.b = 1, 1

    def __iter__(self):
        return self

    def __next__(self):
        c = self.a
        self.a, self.b = self.b, self.a + self.b
        return c

seq = itertools.islice(Fib(), 6)
for x in itertools.combinations(seq, 3):
    print(x)