Class object instance. Link instance attribute to class. Can it be done easier.

[Windspar]

@Gribouillis. I would but Point is just an example. I would have to do that for every method that could change it value.

class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y
    
    def set(self, x, y):
        self.x = x
        self.y = y
        
    def move(self, x, y):
        self.x += x
        self.y += y
        
    # some other properties

Figure out how to do it with __setattr__ and __getattr__.

class LinkObject:
    def __init__(self, value, callback):
        self.read_value = value
        self.callback = callback

    def __call__(self, value=None):
        if value is None:
            return self.read_value
        self.read_value = value
        self.callback()

    def __setattr__(self, instance, value):
        if instance in ['read_value', 'callback']:
            super().__setattr__(instance, value)
        else:
            setattr(self.read_value, instance, value)
            self.callback()

    def __getattr__(self, instance):
        return getattr(self.read_value, instance)

    def clear(self):
        self.read_value = None
        self.callback = callback

Edit. Fix __call__