def successful(self):
        assert self.ready()
        return self._success
Update an image pull progress map with latest download progress
dataset/ETHPy150Open serverdensity/sd-agent/checks/libs/thread_pool.py/ApplyResult.successful--crossover with--dataset/ETHPy150Open signalfx/maestro-ng/maestro/plays/tasks.py/PullTask._update_pull_progress