1 files changed, 2 insertions, 3 deletions

diff --git a/src/mailman/app/moderator.py b/src/mailman/app/moderator.py
index dc5cabd0a..e5fbc9044 100644
--- a/src/mailman/app/moderator.py
+++ b/src/mailman/app/moderator.py
@@ -31,7 +31,6 @@ __all__ = [
     ]
 
 
-import six
 import time
 import logging
 
@@ -87,8 +86,8 @@ def hold_message(mlist, msg, msgdata=None, reason=None):
     message_id = msg.get('message-id')
     if message_id is None:
         msg['Message-ID'] = message_id = make_msgid()
-    assert isinstance(message_id, six.text_type), (
-        'Message-ID is not a unicode: %s' % message_id)
+    elif isinstance(message_id, bytes):
+        message_id = message_id.decode('ascii')
     getUtility(IMessageStore).add(msg)
     # Prepare the message metadata with some extra information needed only by
     # the moderation interface.