diff --git a/Milter/__init__.py b/Milter/__init__.py
index 482dc231a3ab930de8c4d17e4ff89aa874824995..bac61029d58366399e12eccf85496dfbeb721e1d 100755
--- a/Milter/__init__.py
+++ b/Milter/__init__.py
@@ -11,6 +11,7 @@
 __version__ = '0.9.7'
 
 import os
+import re
 import milter
 import thread
 
@@ -48,6 +49,9 @@ OPTIONAL_CALLBACKS = {
   'header':(P_NR_HDR,P_NOHDRS)
 }
 
+## @private
+R = re.compile(r'%+')
+
 ## @private
 def decode_mask(bits,names):
   t = [ (s,getattr(milter,s)) for s in names]