def farmfood():
        foodtype = "Crappy"
        while True:
                fertilizer = (yield ("%s food" % foodtype))
                if fertilizer is not None:
                        foodtype = "Good"
                else:
                        foodtype = "Crappy"

def consumer():
        food = farmfood()
        print food.next()
        print food.send("shit")
        print food.next()

consumer()