diff --git a/mandaye/auth/saml2.py b/mandaye/auth/saml2.py
index 4e7f436..af934e1 100644
--- a/mandaye/auth/saml2.py
+++ b/mandaye/auth/saml2.py
@@ -102,7 +102,7 @@ class SAML2Auth(AuthForm):
             err = "saml2_authnresp_binding: '%s' invalid value (must be artifact, post, redirect or soap)"
             raise ImproperlyConfigured, err
         if name_identifier_format not in NAME_IDENTIFIERS_FORMAT.keys():
-            err = "saml2_authnresp_binding: '%s' invalid value (must be  email, transient, persistent,".\
+            err = "saml2_authnresp_binding: '%s' invalid value (must be  email, transient, persistent," +\
                     " unspecified (username like gapps), encrypted, entity, windows, kerberos or x509)"
             raise ImproperlyConfigured, err
         self.config = {