Remove duplication.
diff --git a/Doc/library/email.message.rst b/Doc/library/email.message.rst
index 1e6a485..3e63258 100644
--- a/Doc/library/email.message.rst
+++ b/Doc/library/email.message.rst
@@ -291,7 +291,7 @@
 
          Content-Disposition: attachment; filename="bud.gif"
 
-      An example with with non-ASCII characters::
+      An example with non-ASCII characters::
 
          msg.add_header('Content-Disposition', 'attachment',
                         filename=('iso-8859-1', '', 'Fußballer.ppt'))