Blinker provides a fast dispatching system that allows any number of interested parties to subscribe to events, or "signals".
[!IMPORTANT]\ This project is part of the Pallets Community Ecosystem. Pallets is the open source organization that maintains Flask; Pallets-Eco enables community maintenance of related projects. If you are interested in helping maintain this project, please reach out on [the Pallets Discord server][discord].
[discord]: https://discord.gg/pallets
Signal receivers can subscribe to specific senders or receive signals sent by any sender.
>>> from blinker import signal
>>> started = signal('round-started')
>>> def each(round):
... print(f"Round {round}")
...
>>> started.connect(each)
>>> def round_two(round):
... print("This is round two.")
...
>>> started.connect(round_two, sender=2)
>>> for round in range(1, 4):
... started.send(round)
...
Round 1!
Round 2!
This is round two.
Round 3!