Add C# += / -= event subscriptions to Python using the Events package

watch_this.py

from events import Events # Note you must pip install events


class Person:

    def __init__(self, name: str, age: int, city: str):
        self.__events = Events(('on_name_changed', 'on_age_changed', 'on_location_changed'))
        self.on_name_changed = self.__events.on_name_changed
        self.on_age_changed = self.__events.on_age_changed
        self.on_location_changed = self.__events.on_location_changed

        self.__name = name
        self.__age = age
        self.__city = city

    @property
    def age(self):
        return self.__age

    @age.setter
    def age(self, value):
        old = self.__age
        self.__age = value

        if old != value:
            self.__events.on_age_changed(self)

    @property
    def name(self):
        return self.__name

    @name.setter
    def name(self, value):
        old = self.__name
        self.__name = value

        if old != value:
            self.__events.on_name_changed(self)

    @property
    def city(self):
        return self.__city

    @city.setter
    def city(self, value):
        old = self.__city
        self.__city = value

        if old != value:
            self.__events.on_location_changed(self)


def main():
    p1 = Person("Michael", 47, "Portland")
    p2 = Person("Zoe", 50, "Orlando")
    p1.on_name_changed += lambda p: print(f"Person changed name to {p.name}.")
    p1.on_location_changed += location_changed
    p2.on_location_changed += location_changed

    # Two moves for Zoe
    p2.city = "Seattle"
    p2.city = "LA"
    # One move for Michael
    p1.city = "Vancouver"

    # One name change for Michael to Mike
    p1.name = "Mike"

    # No longer watching for moves for Michael
    p1.on_location_changed -= location_changed
    p1.city = "Portland"


def location_changed(person: Person):
    print(f"Looks like {person.name} has moved to {person.city}")


if __name__ == '__main__':
    main()

Here's the output I get when running locally:

Looks like Zoe has moved to Seattle
Looks like Zoe has moved to LA
Looks like Michael has moved to Vancouver
Person changed name to Mike.