diff --git a/core/admin/mailu/models.py b/core/admin/mailu/models.py
index 7b58fdac..e99d624d 100644
--- a/core/admin/mailu/models.py
+++ b/core/admin/mailu/models.py
@@ -11,6 +11,20 @@ import time
 import os
 import glob
 import smtplib
+import idna
+
+
+class Idna(db.TypeDecorator):
+    """ Stores a Unicode string in it's IDNA representation (ASCII only)
+    """
+
+    impl = db.String
+
+    def process_bind_param(self, value, dialect):
+        return idna.encode(value)
+
+    def process_result_value(self, value, dialect):
+        return idna.decode(value)
 
 
 # Many-to-many association table for domain managers
@@ -38,19 +52,6 @@ class CommaSeparatedList(db.TypeDecorator):
         return filter(bool, value.split(","))
 
 
-class Idna(db.TypeDecorator):
-    """ Stores a Unicode string in it's IDNA representation (ASCII only)
-    """
-
-    impl = db.String
-
-    def process_bind_param(self, value, dialect):
-        return value.encode("idna")
-
-    def process_result_value(self, value, dialect):
-        return value.decode("idna")
-
-
 class Base(db.Model):
     """ Base class for all models
     """