Iterators in Python

Fib.py

from collections.abc import Iterable, Iterator

class Fib(object):
    def __init__(self):
        self.a, self.b = 0, 1

    def __iter__(self):
        return self

    def __next__(self):
        self.a, self.b = self.b, self.a + self.b
        if self.a > 1000:  # set a limitation to stop
            raise StopIteration()
        return self.a


f = Fib()
print(isinstance(f, Iterator))
print(next(f))
print(next(f))
print(next(f))
print(next(f))

# True
# 1
# 1
# 2
# 3