--- a/doc/tutorials/advanced/part04_ui-base.rst	Thu Feb 21 18:10:47 2019 +0100
+++ b/doc/tutorials/advanced/part04_ui-base.rst	Thu Feb 21 18:15:26 2019 +0100
@@ -23,6 +23,7 @@
 
 .. sourcecode:: python
 
+    from cubicweb import _
     from cubicweb.web import component
     from cubicweb.web.views import error
     from cubicweb.predicates import anonymous_user