diff --git a/diambra/arena/sheeprl/make_sheeprl_env.py b/diambra/arena/sheeprl/make_sheeprl_env.py
index e7da196..d567f9e 100644
--- a/diambra/arena/sheeprl/make_sheeprl_env.py
+++ b/diambra/arena/sheeprl/make_sheeprl_env.py
@@ -61,18 +61,36 @@ def thunk() -> gym.Env:
             instantiate_kwargs["rank"] = rank + vector_env_idx
         env = hydra.utils.instantiate(cfg.env.wrapper, **instantiate_kwargs)
 
+        if not (
+            isinstance(cfg.algo.mlp_keys.encoder, list)
+            and isinstance(cfg.algo.cnn_keys.encoder, list)
+            and len(cfg.algo.cnn_keys.encoder + cfg.algo.mlp_keys.encoder) > 0
+        ):
+            raise ValueError(
+                "`algo.cnn_keys.encoder` and `algo.mlp_keys.encoder` must be lists of strings, got: "
+                f"cnn encoder keys `{cfg.algo.cnn_keys.encoder}` of type `{type(cfg.algo.cnn_keys.encoder)}` "
+                f"and mlp encoder keys `{cfg.algo.mlp_keys.encoder}` of type `{type(cfg.algo.mlp_keys.encoder)}`. "
+                "Both must be non-empty lists."
+            )
+
+        if (
+            len(
+                set(k for k in env.observation_space.keys()).intersection(
+                    set(cfg.algo.mlp_keys.encoder + cfg.algo.cnn_keys.encoder)
+                )
+            )
+            == 0
+        ):
+            raise ValueError(
+                f"The user specified keys `{cfg.algo.mlp_keys.encoder + cfg.algo.cnn_keys.encoder}` "
+                "are not a subset of the "
+                f"environment `{env.observation_space.keys()}` observation keys. Please check your config file."
+            )
+
         env_cnn_keys = set(
-            [
-                k
-                for k in env.observation_space.spaces.keys()
-                if len(env.observation_space[k].shape) in {2, 3}
-            ]
+            [k for k in env.observation_space.spaces.keys() if len(env.observation_space[k].shape) in {2, 3}]
         )
-        if cfg.cnn_keys.encoder is None:
-            user_cnn_keys = set()
-        else:
-            user_cnn_keys = set(cfg.cnn_keys.encoder)
-        cnn_keys = env_cnn_keys.intersection(user_cnn_keys)
+        cnn_keys = env_cnn_keys.intersection(set(cfg.algo.cnn_keys.encoder))
 
         def transform_obs(obs: Dict[str, Any]):
             for k in cnn_keys:
@@ -93,9 +111,7 @@ def transform_obs(obs: Dict[str, Any]):
                 # resize
                 if current_obs.shape[:-1] != (cfg.env.screen_size, cfg.env.screen_size):
                     current_obs = cv2.resize(
-                        current_obs,
-                        (cfg.env.screen_size, cfg.env.screen_size),
-                        interpolation=cv2.INTER_AREA,
+                        current_obs, (cfg.env.screen_size, cfg.env.screen_size), interpolation=cv2.INTER_AREA
                     )
 
                 # to grayscale
@@ -116,14 +132,7 @@ def transform_obs(obs: Dict[str, Any]):
         env = gym.wrappers.TransformObservation(env, transform_obs)
         for k in cnn_keys:
             env.observation_space[k] = gym.spaces.Box(
-                0,
-                255,
-                (
-                    1 if cfg.env.grayscale else 3,
-                    cfg.env.screen_size,
-                    cfg.env.screen_size,
-                ),
-                np.uint8,
+                0, 255, (1 if cfg.env.grayscale else 3, cfg.env.screen_size, cfg.env.screen_size), np.uint8
             )
 
         if cnn_keys is not None and len(cnn_keys) > 0 and cfg.env.frame_stack > 1:
@@ -131,9 +140,7 @@ def transform_obs(obs: Dict[str, Any]):
                 raise ValueError(
                     f"The frame stack dilation argument must be greater than zero, got: {cfg.env.frame_stack_dilation}"
                 )
-            env = FrameStack(
-                env, cfg.env.frame_stack, cnn_keys, cfg.env.frame_stack_dilation
-            )
+            env = FrameStack(env, cfg.env.frame_stack, cnn_keys, cfg.env.frame_stack_dilation)
 
         if cfg.env.reward_as_observation:
             env = RewardAsObservationWrapper(env)
@@ -141,24 +148,15 @@ def transform_obs(obs: Dict[str, Any]):
         env.action_space.seed(seed)
         env.observation_space.seed(seed)
         if cfg.env.max_episode_steps and cfg.env.max_episode_steps > 0:
-            env = gym.wrappers.TimeLimit(
-                env, max_episode_steps=cfg.env.max_episode_steps
-            )
+            env = gym.wrappers.TimeLimit(env, max_episode_steps=cfg.env.max_episode_steps)
         env = gym.wrappers.RecordEpisodeStatistics(env)
-        if (
-            cfg.env.capture_video
-            and rank == 0
-            and vector_env_idx == 0
-            and run_name is not None
-        ):
+        if cfg.env.capture_video and rank == 0 and vector_env_idx == 0 and run_name is not None:
             if cfg.env.grayscale:
                 env = GrayscaleRenderWrapper(env)
             env = gym.experimental.wrappers.RecordVideoV0(
-                env,
-                os.path.join(run_name, prefix + "_videos" if prefix else "videos"),
-                disable_logger=True,
+                env, os.path.join(run_name, prefix + "_videos" if prefix else "videos"), disable_logger=True
             )
             env.metadata["render_fps"] = env.frames_per_sec
         return env
 
-    return thunk
+    return thunk
\ No newline at end of file
diff --git a/setup.py b/setup.py
index ed50d8e..8dc8107 100644
--- a/setup.py
+++ b/setup.py
@@ -23,7 +23,7 @@
     "stable-baselines3": ["stable-baselines3[extra]~=2.1.0", "pyyaml"],
     "ray-rllib": ["ray[rllib]~=2.7.0", "tensorflow", "torch", "pyyaml"],
     "sheeprl": [
-        "sheeprl==0.4.7",
+        "sheeprl==0.4.8",
         "importlib-resources==6.1.0",
     ],
 }