diff --git a/bemani/format/afp/util.py b/bemani/format/afp/util.py
index 455cb04..b1e421d 100644
--- a/bemani/format/afp/util.py
+++ b/bemani/format/afp/util.py
@@ -99,22 +99,22 @@ class VerboseOutputManager:
 
     def __enter__(self) -> "VerboseOutputManager":
         if self.verbose:
-            self.covered_class._verbose = True
+            self.covered_class.verbose = True
         else:
-            self.covered_class._verbose = False
+            self.covered_class.verbose = False
         return self
 
     def __exit__(self, exc_type: Any, exc_val: Any, exc_tb: Any) -> None:
-        self.covered_class._verbose = False
+        self.covered_class.verbose = False
 
 
 class VerboseOutput:
     def __init__(self) -> None:
-        self._verbose: bool = False
+        self.verbose: bool = False
 
     def debugging(self, verbose: bool) -> VerboseOutputManager:
         return VerboseOutputManager(self, verbose)
 
     def vprint(self, *args: Any, **kwargs: Any) -> None:
-        if self._verbose:
+        if self.verbose:
             print(*args, **kwargs, file=sys.stderr)