Update BirdSet.py

BirdSet.py

@@ -552,7 +552,7 @@ class BirdSet(datasets.GeneratorBasedBuilder):
                         "genus": row.get("genus", None),
                         "species_group": row.get("species_group", None),
                         "order": row.get("order", None),
-                        "genus_multilabel": row.get("genus_multilabel", []),
-                        "species_group_multilabel": row.get("species_group_multilabel", []),
-                        "order_multilabel": row.get("order_multilabel", []),
+                        "genus_multilabel": row.get("genus_multilabel", None),
+                        "species_group_multilabel": row.get("species_group_multilabel", None),
+                        "order_multilabel": row.get("order_multilabel", None),
                     }