Built-in Methods

Instance Method vs Static Method

Instance Methods (normal methods without declaring @) specifies with that particular declared instance. For ex. a unique event is specific to a specific calendar instance, and should not exist on other calendar instances.  

Static Method doesn't care about any particular instance. For ex, a weekend on a calendar applies to all calendars since it is universally agreed upon how calendars work, regardless of instance

Also look into Class Method if need to consider inheritance. 

class Calendar:
    def __init__(self):
        self.events = []

    def add_event(self, event):
        self.events.append(event)

    @staticmethod
    def is_weekend(dt):
        pass

Dataclasses