The same thing was done in the previous Piston-DRF conversion and I didn't see it, but that sucks.

Instead of passing the context to the Response, you should just pass the data (in this case, `addons` or `addon_filter(addons, *args)` or `[addon_to_dict(a) for a in addons]`, it's a little unclear while reading the code).

Then, to give your renderer access to the context, you should add stuff to `get_renderer_context()`. DRF `APIView` class will automatically set the dict returned by this method as the context when it renders the response. You'll have access to it via the `renderer_context` argument passed to your renderer's `render()` method.

This allows you to just write something like that:
 `resp = Response(addons, template_name='api/list.xml')`

And it will handle both formats.

Can you look into that for both your code and the previous PR ? Thanks.