--- a/cubicweb/web/views/urlrewrite.py	Fri Apr 05 17:21:14 2019 +0200
+++ b/cubicweb/web/views/urlrewrite.py	Fri Apr 05 17:58:19 2019 +0200
@@ -19,8 +19,6 @@
 
 import re
 
-from six import string_types, add_metaclass
-
 from cubicweb.uilib import domid
 from cubicweb.appobject import AppObject
 
@@ -53,8 +51,7 @@
         return super(metarewriter, mcs).__new__(mcs, name, bases, classdict)
 
 
-@add_metaclass(metarewriter)
-class URLRewriter(AppObject):
+class URLRewriter(AppObject, metaclass=metarewriter):
     """Base class for URL rewriters.
 
     Url rewriters should have a `rules` dict that maps an input URI
@@ -124,14 +121,14 @@
                 required_groups = None
             if required_groups and not req.user.matching_groups(required_groups):
                 continue
-            if isinstance(inputurl, string_types):
+            if isinstance(inputurl, str):
                 if inputurl == uri:
                     req.form.update(infos)
                     break
             elif inputurl.match(uri): # it's a regexp
                 # XXX what about i18n? (vtitle for instance)
                 for param, value in infos.items():
-                    if isinstance(value, string_types):
+                    if isinstance(value, str):
                         req.form[param] = inputurl.sub(value, uri)
                     else:
                         req.form[param] = value
@@ -224,7 +221,7 @@
                 required_groups = None
             if required_groups and not req.user.matching_groups(required_groups):
                 continue
-            if isinstance(inputurl, string_types):
+            if isinstance(inputurl, str):
                 if inputurl == uri:
                     return callback(inputurl, uri, req, self._cw.vreg.schema)
             elif inputurl.match(uri): # it's a regexp