diff --git a/authens/backends.py b/authens/backends.py
index fb164a7..c077716 100644
--- a/authens/backends.py
+++ b/authens/backends.py
@@ -43,7 +43,7 @@ class ENSCASBackend:
     def clean_cas_login(self, cas_login):
         return cas_login.strip().lower()
 
-    def get_free_username(self, cas_login):
+    def get_free_username(self, cas_login, attributes):
         """Find an available username for a new user.
 
         If you override this method, make sure it returns a username that is not taken
@@ -102,7 +102,7 @@ class ENSCASBackend:
                 user = None
 
             if user is None:
-                username = self.get_free_username(cas_login)
+                username = self.get_free_username(cas_login, attributes)
                 user = UserModel.objects.create_user(username=username, email=email)
                 CASAccount.objects.create(
                     user=user, entrance_year=entrance_year, cas_login=cas_login