really really simple pub/sub in python

simple_pubsub.py

class Publisher:
    def __init__(self):
        self.subscribers = []

    def publish(self, message):
        print("publishing message: {msg}".format(msg=message))
        for subscriber in self.subscribers:
            subscriber.onReceive(message)

    def addSubscriber(self, subscriber):
        self.subscribers.append(subscriber)

class Subscriber:
    def subscribeTo(self, publisher, onReceive):
        publisher.addSubscriber(self)
        self.onReceive = onReceive

p = Publisher()
s1 = Subscriber()
s2 = Subscriber()

s1.subscribeTo(p, lambda message: print("S1 received: {msg}".format(msg=message)))
s2.subscribeTo(p, lambda message: print("S2 received: {msg}".format(msg=message)))

p.publish("test message")