Address more comments

README.md

@@ -148,9 +148,9 @@ DATA_DIR="tests/data" pytest -sx tests
 
 **Datasets**
 
-To add a pytorch rl dataset to the hub, first login and use a token generated from [huggingface settings](https://huggingface.co/settings/tokens) with write access:
+To add a dataset to the hub, first login and use a token generated from [huggingface settings](https://huggingface.co/settings/tokens) with write access:
 ```
-huggingface-cli login --token $HUGGINGFACE_TOKEN --add-to-git-credential
+huggingface-cli login --token ${HUGGINGFACE_TOKEN} --add-to-git-credential
 ```
 
 Then you can upload it to the hub with:
@@ -160,6 +160,12 @@ HF_HUB_ENABLE_HF_TRANSFER=1 huggingface-cli upload $HF_USER/$DATASET data/$DATAS
 --revision v1.0
 ```
 
+You will need to set the corresponding version as a default argument in your dataset class:
+```python
+  version: str | None = "v1.0",
+```
+See: [`lerobot/common/datasets/pusht.py`](https://github.com/Cadene/lerobot/blob/main/lerobot/common/datasets/pusht.py)
+
 For instance, for [cadene/pusht](https://huggingface.co/datasets/cadene/pusht), we used:
 ```
 HF_USER=cadene
@@ -169,7 +175,7 @@ DATASET=pusht
 If you want to improve an existing dataset, you can download it locally with:
 ```
 mkdir -p data/$DATASET
-HF_HUB_ENABLE_HF_TRANSFER=1 huggingface-cli download $HF_USER/$DATASET \
+HF_HUB_ENABLE_HF_TRANSFER=1 huggingface-cli download ${HF_USER}/$DATASET \
 --repo-type dataset \
 --local-dir data/$DATASET \
 --local-dir-use-symlinks=False \
@@ -181,15 +187,22 @@ Iterate on your code and dataset with:
 DATA_DIR=data python train.py
 ```
 
-Then upload a new version (v2.0 or v1.1 if the changes are respectively more or less significant):
+Upload a new version (v2.0 or v1.1 if the changes are respectively more or less significant):
 ```
 HF_HUB_ENABLE_HF_TRANSFER=1 huggingface-cli upload $HF_USER/$DATASET data/$DATASET \
 --repo-type dataset \
 --revision v1.1 \
 --delete "*"
 ```
 
-And you might want to mock the dataset if you need to update the unit tests as well:
+Then you will need to set the corresponding version as a default argument in your dataset class:
+```python
+  version: str | None = "v1.1",
+```
+See: [`lerobot/common/datasets/pusht.py`](https://github.com/Cadene/lerobot/blob/main/lerobot/common/datasets/pusht.py)
+
+
+Finally, you might want to mock the dataset if you need to update the unit tests as well:
 ```
 python tests/scripts/mock_dataset.py --in-data-dir data/$DATASET --out-data-dir tests/data/$DATASET
 ```

lerobot/common/datasets/abstract.py

@@ -35,6 +35,12 @@ def __init__(
         self.version = version
         self.shuffle = shuffle
         self.root = root
+
+        if self.root is not None and self.version is not None:
+            logging.warning(
+                f"The version of the dataset ({self.version}) is not enforced when root is provided ({self.root})."
+            )
+
         storage = self._download_or_load_dataset()
 
         super().__init__(