diff --git a/egs/vctk/TTS/vits/infer.py b/egs/vctk/TTS/vits/infer.py
index 17c08ad40..bd823019f 100755
--- a/egs/vctk/TTS/vits/infer.py
+++ b/egs/vctk/TTS/vits/infer.py
@@ -247,7 +247,12 @@ def main():
     valid_cuts = vctk.valid_cuts()
     valid_dl = vctk.valid_dataloaders(valid_cuts)
 
-    infer_sets = {"test", test_dl, "valid", valid_dl}
+    infer_sets: Dict = {
+        "test",
+        test_dl,
+        "valid",
+        valid_dl,
+    }
 
     for subset, dl in infer_sets.items():
         save_wav_dir = params.res_dir / "wav" / subset