def normalize_name(name):
     """
     >>> normalize_name("gąska".decode('utf-8'))
-    u'gaska'
+    u'g\u0105ska'
     """
     return name.translate(_PCHARS_DICT).lower()
 
         text, rev = self.vstorage.page_text_by_tag(name, tag)
         return Document(self, name=name, text=text, revision=rev)
 
+    def revert(self, name, revision):
+        text, rev = self.vstorage.revert(name, revision)
+        return Document(self, name=name, text=text, revision=rev)
+
     def get_or_404(self, *args, **kwargs):
         try:
             return self.get(*args, **kwargs)
 
     def traceback(self, exc=None):
         if exc is not None: self.__logger.exception()
 
-    def progress(self, *args):
+    def progress(self, *args, **kwargs):
         pass