diff --git a/src/litdata/utilities/dataset_utilities.py b/src/litdata/utilities/dataset_utilities.py
index 45a1bd6c..3abe1b41 100644
--- a/src/litdata/utilities/dataset_utilities.py
+++ b/src/litdata/utilities/dataset_utilities.py
@@ -131,6 +131,7 @@ def load_index_file(input_dir: str) -> Dict[str, Any]:
     Raises:
         ValueError: If the index file format is invalid.
         FileNotFoundError: If the index file does not exist in the input directory.
+
     """
     index_filepath = os.path.join(input_dir, _INDEX_FILENAME)
     try:
@@ -139,10 +140,9 @@ def load_index_file(input_dir: str) -> Dict[str, Any]:
 
         if "chunks" in data:
             return data
-        elif "shards" in data:
+        if "shards" in data:
             return adapt_mds_shards_to_chunks(data)
-        else:
-            raise ValueError(f"Invalid index file format at {index_filepath}.")
+        raise ValueError(f"Invalid index file format at {index_filepath}.")
     except FileNotFoundError:
         raise FileNotFoundError(f"Index file not found at {index_filepath}.")
 
diff --git a/tests/streaming/test_dataset.py b/tests/streaming/test_dataset.py
index e37cc111..2384dd81 100644
--- a/tests/streaming/test_dataset.py
+++ b/tests/streaming/test_dataset.py
@@ -996,6 +996,7 @@ def test_subsample_streaming_dataset_with_token_loader(tmpdir, monkeypatch):
 
     assert len(dataset2) == int(len(dataset1) * 0.4)
 
+
 @pytest.mark.skipif(sys.platform == "win32", reason="Not tested on windows")
 def test_dataset_with_mosaic_mds_data(tmpdir):
     from PIL import Image