469     """main template are primary access point to render a full HTML page.

   469     """main template are primary access point to render a full HTML page.

   470     There is usually at least a regular main template and a simple fallback

   470     There is usually at least a regular main template and a simple fallback

   471     one to display error if the first one failed

   471     one to display error if the first one failed

   472     """

   472     """

   473 

   473 

   475 

   475 

   476     def set_stream(self, w=None):

   476     def set_stream(self, w=None):

   477         if self.w is not None:

   477         if self.w is not None:

   478             return

   478             return

   479         if w is None:

   479         if w is None: