diff --git a/composer/schema/field.py b/composer/schema/field.py
index bdef21a..531be50 100644
--- a/composer/schema/field.py
+++ b/composer/schema/field.py
@@ -337,7 +337,7 @@ class ListFieldInstance(FieldInstance):
             return value
         if value is None:
             return u''
-        return u'\n'.join(self.valueFieldInstance.marshall(v) for v in value)
+        return u'\n'.join(unicode(self.valueFieldInstance.marshall(v)) for v in value)
         #return [self.valueFieldInstance.marshall(v) for v in value]
 
     def display(self, value):