Minor fix to data loader script

xsum.py

@@ -93,7 +93,7 @@ class Xsum(datasets.GeneratorBasedBuilder):
 
     def _generate_examples(self, filepath, split, filepaths=None, lang=None):
         """Yields examples."""
-	if "challenge" in split:
+        if "challenge" in split:
             if "covid" in split:
                 with open(filepath, encoding="utf-8") as f:
                     id_ = -1