try fix 3

src/lerobot/datasets/lerobot_dataset.py

@@ -80,6 +80,33 @@ from lerobot.utils.constants import HF_LEROBOT_HOME
 CODEBASE_VERSION = "v3.0"
 
 
+def hf_transform_to_torch(items_dict: dict[str, list[Any]]) -> dict[str, list[torch.Tensor | str]]:
+    """Convert a batch from a Hugging Face dataset to torch tensors.
+
+    This transform function converts items from Hugging Face dataset format (pyarrow)
+    to torch tensors. Importantly, images are converted from PIL objects (H, W, C, uint8)
+    to a torch image representation (C, H, W, float32) in the range [0, 1]. Other
+    types are converted to torch.tensor.
+
+    Args:
+        items_dict (dict): A dictionary representing a batch of data from a
+            Hugging Face dataset.
+
+    Returns:
+        dict: The batch with items converted to torch tensors.
+    """
+    for key in items_dict:
+        first_item = items_dict[key][0]
+        if isinstance(first_item, PILImage.Image):
+            to_tensor = transforms.ToTensor()
+            items_dict[key] = [to_tensor(img) for img in items_dict[key]]
+        elif first_item is None:
+            pass
+        else:
+            items_dict[key] = [x if isinstance(x, str) else torch.tensor(x) for x in items_dict[key]]
+    return items_dict
+
+
 class LeRobotDatasetMetadata:
     def __init__(
         self,
@@ -834,10 +861,6 @@ class LeRobotDataset(torch.utils.data.Dataset):
     def load_hf_dataset(self) -> datasets.Dataset:
         """hf_dataset contains all the observations, states, actions, rewards, etc."""
 
-        # We MUST import this here to avoid circular dependency
-        # (utils imports lerobot_dataset for backward_compatibility)
-        from lerobot.datasets.utils import hf_transform_to_torch
-
         features = get_hf_features_from_features(self.features)
 
         # This is the v2.1 logic that forces an efficient, pre-decoded cache build.
@@ -1718,30 +1741,3 @@ class MultiLeRobotDataset(torch.utils.data.Dataset):
             f"  Transformations: {self.image_transforms},\n"
             f")"
         )
-
-
-def hf_transform_to_torch(items_dict: dict[str, list[Any]]) -> dict[str, list[torch.Tensor | str]]:
-    """Convert a batch from a Hugging Face dataset to torch tensors.
-
-    This transform function converts items from Hugging Face dataset format (pyarrow)
-    to torch tensors. Importantly, images are converted from PIL objects (H, W, C, uint8)
-    to a torch image representation (C, H, W, float32) in the range [0, 1]. Other
-    types are converted to torch.tensor.
-
-    Args:
-        items_dict (dict): A dictionary representing a batch of data from a
-            Hugging Face dataset.
-
-    Returns:
-        dict: The batch with items converted to torch tensors.
-    """
-    for key in items_dict:
-        first_item = items_dict[key][0]
-        if isinstance(first_item, PILImage.Image):
-            to_tensor = transforms.ToTensor()
-            items_dict[key] = [to_tensor(img) for img in items_dict[key]]
-        elif first_item is None:
-            pass
-        else:
-            items_dict[key] = [x if isinstance(x, str) else torch.tensor(x) for x in items_dict[key]]
-    return items_dict