type check hints for features

automata.py

@@ -1,5 +1,5 @@
 # Copyright 2020 The HuggingFace Datasets Authors.
-# Copyright 2023 Cyril Zhang.
+# Copyright 2023 Bingbin Liu, Jordan Ash, Surbhi Goel, Akshay Krishnamurthy, and Cyril Zhang.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -61,8 +61,8 @@ class MockupDataset(datasets.GeneratorBasedBuilder):
     def _info(self):
         features = datasets.Features(
             {
-                "x": datasets.Value("null"),
-                "y": datasets.Value("null")
+                "x": datasets.Sequence(datasets.Value("int32"), length=-1),
+                "y": datasets.Sequence(datasets.Value("int32"), length=-1)
             }
         )