diff --git a/seahub/invitations/models.py b/seahub/invitations/models.py
index 6e6d0b364d..e816e591c6 100644
--- a/seahub/invitations/models.py
+++ b/seahub/invitations/models.py
@@ -40,7 +40,7 @@ class InvitationManager(models.Manager):
 
 class Invitation(models.Model):
     INVITE_TYPE_CHOICES = (
-        (GUEST, _('Guest')),
+        (GUEST, 'Guest'),
     )
 
     token = models.CharField(max_length=40, db_index=True)