Whitespace normalization.
diff --git a/Lib/rfc822.py b/Lib/rfc822.py
index 4b12c4b..3d9e13f 100644
--- a/Lib/rfc822.py
+++ b/Lib/rfc822.py
@@ -443,7 +443,7 @@
 
     def __contains__(self, name):
         """Determine whether a message contains the named header."""
-        return name.lower() in self.dict        
+        return name.lower() in self.dict
 
     def keys(self):
         """Get all of a message's header field names."""