--- a/cubicweb/web/views/tabs.py	Fri Apr 05 17:21:14 2019 +0200
+++ b/cubicweb/web/views/tabs.py	Fri Apr 05 17:58:19 2019 +0200
@@ -20,8 +20,6 @@
 
 from cubicweb import _
 
-from six import string_types
-
 from logilab.common.deprecation import class_renamed
 from logilab.mtconverter import xml_escape
 
@@ -116,7 +114,7 @@
         active_tab = uilib.domid(default_tab)
         viewsvreg = self._cw.vreg['views']
         for tab in tabs:
-            if isinstance(tab, string_types):
+            if isinstance(tab, str):
                 tabid, tabkwargs = tab, {}
             else:
                 tabid, tabkwargs = tab