i have no idea how this feature thing works

unigram.py

@@ -67,8 +67,8 @@ class unigram(evaluate.Metric):
             inputs_description=_KWARGS_DESCRIPTION,
             # This defines the format of each prediction and reference
             features=datasets.Features({
-                'predictions': datasets.Sequence(datasets.Sequence(datasets.Value('int64'))),
-                'references': datasets.Sequence(datasets.Sequence(datasets.Value('int64'))),
+                'predictions': datasets.Sequence(datasets.Value('int64')),
+                'references': datasets.Sequence(datasets.Value('int64')),
             }),
             # Homepage of the module for documentation
             homepage="http://module.homepage",