# Copyright 2020 (c) Anna Schumaker.

class Publisher:
    def __init__(self):
        self.subscribers = set()

    def publish(self, *args):
        funcs = self.subscribers.copy()
        for func in funcs:
            func(*args)

    def register(self, func):
        self.subscribers.add(func)

    def reset(self):
        self.subscribers.clear()

    def unregister(self, func):
        self.subscribers.discard(func)