def wsgi_extend(self, controller):
<EOL>for key, action in controller.wsgi_actions.items():<EOL><INDENT>if self.wsgi_mapper and key not in self.wsgi_actions:<EOL><INDENT>self._route(key, action)<EOL><DEDENT>self.wsgi_actions[key] = action<EOL>self.wsgi_descriptors.pop(key, None)<EOL><DEDENT>for key, extensions in controller.wsgi_extensions.items():<EOL><INDENT>if not extensions:<EOL><INDENT>continue<EOL><DEDENT>self.wsgi_extensions.setdefault(key, [])<EOL>self.wsgi_extensions[key].extend(extensions)<EOL>self.wsgi_descriptors.pop(key, None)<EOL><DEDENT>
Extends a controller by registering another controller as an
extension of it.  All actions defined on the extension
controller have routes generated for them (only if none
already exist) and are made actions of this controller; all
extensions defined on the extension controller are added to
the extensions registered on this controller.