fix input format

ece.py

@@ -76,7 +76,7 @@ class ECE(evaluate.Metric):
             inputs_description=_KWARGS_DESCRIPTION,
             # This defines the format of each prediction and reference
             features=datasets.Features({
-                'predictions': datasets.Value('float32'),
+                'predictions': datasets.Sequence(datasets.Value('float32')),
                 'references': datasets.Value('int64'),
             }),
             # Homepage of the module for documentation