better handling of format param

Author: Richard Jones

roundup/cgi/templating.py

@@ -988,15 +988,19 @@ def reldate(self, pretty=1):
             return interval.pretty()
         return str(interval)
 
-    def pretty(self, format='%d %B %Y'):
+    _marker = []
+    def pretty(self, format=_marker):
         ''' Render the date in a pretty format (eg. month names, spaces).
 
             The format string is a standard python strftime format string.
             Note that if the day is zero, and appears at the start of the
             string, then it'll be stripped from the output. This is handy
             for the situatin when a date only specifies a month and a year.
         '''
-        return self._value.pretty()
+        if format is not self._marker:
+            return self._value.pretty(format)
+        else:
+            return self._value.pretty()
 
     def local(self, offset):
         ''' Return the date/time as a local (timezone offset) date/time.