# Error when loading and restoring a trained algorithm from a checkpoint using a APPO Algorithm

**URL:** <https://discuss.ray.io/t/error-when-loading-and-restoring-a-trained-algorithm-from-a-checkpoint-using-a-appo-algorithm/9368>\
**Category:** RLlib\
**Created:** [February 14, 2023, 9:45am UTC](https://discuss.ray.io/t/error-when-loading-and-restoring-a-trained-algorithm-from-a-checkpoint-using-a-appo-algorithm/9368 "2023-02-14T09:45:14Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Giovanni\_Febbraro](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/giovanni_febbraro/32/3888_2.png) [@Giovanni\_Febbraro](https://discuss.ray.io/u/Giovanni_Febbraro)\
**Post date:** [February 14, 2023, 9:45am UTC](https://discuss.ray.io/t/error-when-loading-and-restoring-a-trained-algorithm-from-a-checkpoint-using-a-appo-algorithm/9368/1 "2023-02-14T09:45:14Z")

</div>

Hello everybody,  
I trained a RL Model using a _.train()_ method and I saved the results in a folder with the _.save()_ method.

Then I try to restore with:

```auto
from ray.rllib.algorithms.algorithm import Algorithm
algo_2 = Algorithm.from_checkpoint(checkpoint_path_2)

```

but the error I got is:

```auto
TypeError Traceback (most recent call last)
Cell In [14], line 2
      1 from ray.rllib.algorithms.algorithm import Algorithm
----> 2 algo_2 = Algorithm.from_checkpoint(checkpoint_path_2)

File ~\Anaconda3\lib\site-packages\ray\rllib\algorithms\algorithm.py:270, in Algorithm.from_checkpoint(checkpoint, policy_ids, policy_mapping_fn, policies_to_train)
    263 if checkpoint_info["checkpoint_version"] < version.Version("1.0"):
    264 raise ValueError(
    265 "`checkpoint_info['checkpoint_version']` in `Algorithm.from_checkpoint"
    266 "()` must be 1.0 or later! You are using a checkpoint with "
    267 f"version v{checkpoint_info['checkpoint_version']}."
    268 )
--> 270 state = Algorithm._checkpoint_info_to_algorithm_state(
    271 checkpoint_info=checkpoint_info,
    272 policy_ids=policy_ids,
    273 policy_mapping_fn=policy_mapping_fn,
    274 policies_to_train=policies_to_train,
    275 )
    277 return Algorithm.from_state(state)

File ~\Anaconda3\lib\site-packages\ray\rllib\algorithms\algorithm.py:2857, in Algorithm._checkpoint_info_to_algorithm_state(checkpoint_info, policy_ids, policy_mapping_fn, policies_to_train)
   2851 worker_state["filters"] = {
   2852 pid: filter
   2853 for pid, filter in worker_state["filters"].items()
   2854 if pid in policy_ids
   2855 }
   2856 # Remove policies from multiagent dict that are not in `policy_ids`.
-> 2857 policies_dict = state["config"]["multiagent"]["policies"]
   2858 policies_dict = {
   2859 pid: spec for pid, spec in policies_dict.items() if pid in policy_ids
   2860 }
   2861 state["config"]["multiagent"]["policies"] = policies_dict

TypeError: 'PPOConfig' object is not subscriptable

```

---

<div class="post-metadata">

**Author:** ![mannyv](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/mannyv/32/606_2.png) [@mannyv](https://discuss.ray.io/u/mannyv)\
**Post date:** [February 14, 2023, 7:12pm UTC](https://discuss.ray.io/t/error-when-loading-and-restoring-a-trained-algorithm-from-a-checkpoint-using-a-appo-algorithm/9368/2 "2023-02-14T19:12:55Z")

</div>

Hi @Giovanni_Febbraro,

Welcome to the forums.

state[“config”] is not a dictionary it is an AlgorithmConfig object.

> <https://github.com/ray-project/ray/blob/bf5e721780a4cc757c7c613e79c26cea7300a834/rllib/algorithms/algorithm_config.py#L118>