import rx

stream = rx.subject.Subject()

c = stream.pipe(
#     ops.take_while(lambda i: i < 60)
    ops.filter(lambda i: i < 60)
)
c.subscribe(on_next=lambda i: print("i is {}".format(i)))

stream.on_next(0)
stream.on_next(50)
stream.on_next(51)
stream.on_next(49)
stream.on_next(100)
stream.on_next(-50)