diff --git a/sample.py b/sample.py
index a3456e3..a5de567 100644
--- a/sample.py
+++ b/sample.py
@@ -50,10 +50,13 @@
 speechset.utils.mp_dump(acoustic, DUMP_PATH, 4)
 
 # load dump
-dumped = speechset.utils.DumpDataset(
-    speechset.AcousticDataset, DUMP_PATH)
+class WrappedAcoustic(speechset.utils.IDWrapper):
+    def __init__(self, *args, **kwargs):
+        super().__init__(speechset.AcousticDataset(*args, **kwargs))
+
+dumped = speechset.utils.DumpDataset(WrappedAcoustic, DUMP_PATH)
 
 # unpack
-sid, text, mel, textlen, mellen = acoustic[0:3]
+sid, text, mel, textlen, mellen = dumped[0:3]
 print(sid.shape, text.shape, mel.shape, textlen.shape, mellen.shape)
 
diff --git a/utils/dump.py b/utils/dump.py
index ba1fa97..0dca4e2 100644
--- a/utils/dump.py
+++ b/utils/dump.py
@@ -43,7 +43,7 @@ def preprocessor(path: str) -> Any:
             Returns:
                 loaded.
             """
-            return np.load(path, allow_pickle=True).item()
+            return np.load(path, allow_pickle=True)
 
         return preprocessor