[fix] Change the expected type of input

eval_keyphrase.py

@@ -73,8 +73,8 @@ class eval_keyphrase(evaluate.Metric):
             inputs_description=_KWARGS_DESCRIPTION,
             # This defines the format of each prediction and reference
             features=datasets.Features({
-                'predictions': datasets.Value('int64'),
-                'references': datasets.Value('int64'),
+                'predictions': datasets.Sequence(datasets.Value('string')),
+                'references': datasets.Sequence(datasets.Value('string')),
             }),
             # Homepage of the module for documentation
             homepage="http://module.homepage",