setting a class attribute using a class method in python

Question

I have a class with a few class attributes, that I would like to initialize by using class methods. This is because I have close to 300 items in a list, and I'd rather not have them in the class definition. Since I will be having at minimum, upwards of a few hundred objects of this class, It wouldn't be efficient to read and then create a attribute for each individual instantiation when they won't be modifiying the two lists I've defined, and only reading from them.

class exampleClass:

    @classmethod
    def getUnsupportedEvents(cls):
        with open("randomfile.json") as file:
            return json.load(file)

    supportedEvents = []
    unsupportedEvents = getUnsupportedEvents()

I want to set the class attribute unsupportedEvent using the classmethod getUnsupportedEvents() , but when I attempt to do so in the above way, I get the following error:

unsupportedEvents = getUnsupportedEvents()

TypeError: 'classmethod' object is not callable

This seems really simple, am I just overlooking something really easy?

Answer 1

You are trying to use a class method before the class is fully defined. You must delay the call after the definition:

class exampleClass:

    @classmethod
    def getUnsupportedEvents(cls):
        with open("randomfile.json") as file:
            return json.load(file)

    supportedEvents = []

exampleClass.unsupportedEvents = exampleClass.getUnsuportedEvents()