diff --git a/style_bert_vits2/nlp/chinese/bert_feature.py b/style_bert_vits2/nlp/chinese/bert_feature.py
index 95b7848..9ff997d 100644
--- a/style_bert_vits2/nlp/chinese/bert_feature.py
+++ b/style_bert_vits2/nlp/chinese/bert_feature.py
@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Any, Optional, Sequence, Union, cast
+from typing import TYPE_CHECKING, Any, Optional, Sequence, Union
 
 import numpy as np
 from numpy.typing import NDArray
diff --git a/style_bert_vits2/nlp/english/bert_feature.py b/style_bert_vits2/nlp/english/bert_feature.py
index 94987dd..5c3e24f 100644
--- a/style_bert_vits2/nlp/english/bert_feature.py
+++ b/style_bert_vits2/nlp/english/bert_feature.py
@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Any, Optional, Sequence, Union, cast
+from typing import TYPE_CHECKING, Any, Optional, Sequence, Union
 
 import numpy as np
 from numpy.typing import NDArray
diff --git a/style_bert_vits2/nlp/japanese/bert_feature.py b/style_bert_vits2/nlp/japanese/bert_feature.py
index 0d418d3..079ca85 100644
--- a/style_bert_vits2/nlp/japanese/bert_feature.py
+++ b/style_bert_vits2/nlp/japanese/bert_feature.py
@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Any, Optional, Sequence, Union, cast
+from typing import TYPE_CHECKING, Any, Optional, Sequence, Union
 
 import numpy as np
 from numpy.typing import NDArray