diff --git a/keystoneclient_kerberos/__init__.py b/keystoneclient_kerberos/__init__.py
index a15e5a6..034a282 100644
--- a/keystoneclient_kerberos/__init__.py
+++ b/keystoneclient_kerberos/__init__.py
@@ -22,5 +22,5 @@ __version__ = pbr.version.VersionInfo(
 V3Kerberos = v3.Kerberos
 V3FederatedKerberos = v3.FederatedKerberos
 
-__all__ = ['V3FederatedKerberos',
-           'V3Kerberos']
+__all__ = ('V3FederatedKerberos',
+           'V3Kerberos')