C# style event handler

event_handler.py

from typing import Callable, Generic, TypeVar

T = TypeVar("T")

class EventHandler(Generic[T]):
	callbacks: list [Callable[[T], None]] = []

	def __iadd__(self, callback: Callable[[T], None]):
		self.callbacks.append(callback)
		return self

	def __isub__(self, callback: Callable[[T], None]):
		self.callbacks.remove(callback)
		return self

	def invoke(self, value: T):
		for cb in self.callbacks:
			cb(value)

	def __call__(self, value: T):
		self.invoke(value)


# -------------------------------- Testing -------------------------------------

def some_other_func(string: str):
	print(f"nice! {string}")

def another_one(string: str):
	print(f"eww: {string}")

def main():
	s: EventHandler[str] = EventHandler()

	# adding some callbacks
	s += lambda v: print(v)
	s += lambda v: print(f"I'm also being called! msg: {v}")
	s += some_other_func
	s += another_one

	s -= another_one # eh, too mean, we'll just remove it

	s.invoke("this is a message")
	s("another one!")