diff --git a/post_processor/post_processor.h b/post_processor/post_processor.h
index bbeed9a..ffba3d3 100644
--- a/post_processor/post_processor.h
+++ b/post_processor/post_processor.h
@@ -63,8 +63,9 @@ class PostProcessor {
 
   void InitITNResource(const std::string& tagger_path,
                        const std::string& verbalizer_path);
-
- public:
+  private:
+    const PostProcessOptions opts_;
+  public:
   WENET_DISALLOW_COPY_AND_ASSIGN(PostProcessor);
 };