Storing list of instances (of self) in class level attribute?

Question

I have a class in which I would like to store a static reference list of objects of the same class. For example:

class Apple:

    NICE_APPLES = [Apple('Elstar', 'Green'), Apple('Braeburn', 'Red'), 
        Apple('Pink Lady', 'Pink')]

    def __init__(self, name, colour):
        self.name = name
        self.colour = colour

This results in a NameError: name 'Apple' is not defined error. Why doesn't this work?

I've changed the code to the following, which seems to work on the console:

class Apple:

    NICE_APPLES = []

    def __init__(self, name, colour):
        self.name = name
        self.colour = colour

Apple.NICE_APPLES = [Apple('Elstar', 'Green'), Apple('Braeburn', 'Red'), 
        Apple('Pink Lady', 'Pink')]

Is there a better way to do this? Will this work inside and outside the module, and is this dependent on the way I import the module?

Answer 1

use a classmethod to append apples to your class list.

class Apple:

    NICE_APPLES = []

    def __init__(self, name, colour):
        self.name = name
        self.colour = colour

    @classmethod
    def add_nice_apple(cls, name, colour):
        cls.NICE_APPLES.append(cls(name, colour))


Apple.add_nice_apple('Elstar','Green')
Apple.add_nice_apple('Braeburn','Red')