Partial introduction of bools where appropriate.
diff --git a/Lib/rfc822.py b/Lib/rfc822.py
index 96ab21c..65957ab 100644
--- a/Lib/rfc822.py
+++ b/Lib/rfc822.py
@@ -222,7 +222,7 @@
         data in RFC 2822-like formats that support embedded comments or
         free-text data.
         """
-        return None
+        return False
 
     def getallmatchingheaders(self, name):
         """Find all header lines matching a given header name.