[Zope] Returning generated gif via __getattr__

I have a gif image that I would like to return via a __getattr__ method. But I have no clues as to how I can do it. img_data # binary image data # The problem below is that it needs a docstring to get published. def __getattr__(self, attr): if attr = 'gif_image': return img_data # and if I write: def gif_image(self): "docstring" return img_data The browser does not recognise the mime type. Does anybody else have a clue as to what I need to do? regards Max M