def METHOD_NAME(self):
    global INSTANCE_IDENTIFIER
    if INSTANCE_IDENTIFIER:
        return INSTANCE_IDENTIFIER
    instance_identifier = self.settings.get("instance_identifier")
    if not instance_identifier:
        INSTANCE_IDENTIFIER = uuid.uuid4()
        self.settings.set("instance_identifier", str(instance_identifier))
    else:
        INSTANCE_IDENTIFIER = uuid.UUID(instance_identifier)
    return INSTANCE_IDENTIFIER