diff --git a/deepspeech/io/dataset.py b/deepspeech/io/dataset.py
index fc6879026..929a6cf85 100644
--- a/deepspeech/io/dataset.py
+++ b/deepspeech/io/dataset.py
@@ -249,22 +249,22 @@ class ManifestDataset(Dataset):
 
 
 
-    def _instance_reader_creator(self, manifest):
-        """
-        Instance reader creator. Create a callable function to produce
-        instances of data.
-
-        Instance: a tuple of ndarray of audio spectrogram and a list of
-        token indices for transcript.
-        """
-
-        def reader():
-            for instance in manifest:
-                inst = self.process_utterance(instance["utt"], instance["feat"],
-                                              instance["text"])
-                yield inst
-
-        return reader
+    # def _instance_reader_creator(self, manifest):
+    #     """
+    #     Instance reader creator. Create a callable function to produce
+    #     instances of data.
+
+    #     Instance: a tuple of ndarray of audio spectrogram and a list of
+    #     token indices for transcript.
+    #     """
+
+    #     def reader():
+    #         for instance in manifest:
+    #             inst = self.process_utterance(instance["utt"], instance["feat"],
+    #                                           instance["text"])
+    #             yield inst
+
+    #     return reader
 
     def __len__(self):
         return len(self._manifest)