return empty df when loading leaderboard dataset error

app_leaderboard.py

@@ -2,6 +2,7 @@ import logging
 
 import datasets
 import gradio as gr
+import pandas as pd
 
 from fetch_utils import (check_dataset_and_get_config,
                          check_dataset_and_get_split)
@@ -24,7 +25,7 @@ def get_records_from_dataset_repo(dataset_id):
         logger.warning(
             f"Failed to load dataset {dataset_id} with config {dataset_config}: {e}"
         )
-        return None
+        return pd.DataFrame()
 
     
 def get_model_ids(ds):