'Create a key that is derived from the generation.'

def key(self, *args, **kwargs):

    base_key = super(GenerationJob, self).key(*args, **kwargs)
    gen_key = self.generation_key.key()
    gen_key_value = self.generation_key.get()
    return ('%s@%s:%s' % (base_key, gen_key, gen_key_value))
