canvas.render doesn't accept None as second parameter

[John Coppens <john jcoppens com>]

Hi all,

> From a demo I found on the 'net, I used:

        surface = cairo.SVGSurface("demo.svg", 9 * 72, 10 * 72)
        cr = cairo.Context(surface)
        self.canvas.render(cr, None, 1)

This prints:

Traceback (most recent call last):
  File "necview.py", line 351, in save_SVG
    self.canvas.render(cr, None, 1)
  File "/usr/lib64/python2.7/site-packages/gi/types.py", line 44, in function
    return info.invoke(*args)
TypeError: argument 2: Must be GooCanvas.CanvasBounds, not NoneType

According to https://lazka.github.io/pgi-docs/GooCanvas-2.0/classes/Canvas.html#GooCanvas.Canvas.render
render should accept None as second parameter.

1) Is this a doc error or a GI/Goocanvas regression?
2) I couldn't find a working demo which uses 'render' and SVG|PNG...surfaces in python. 

BTW, I have GooCanvas 2.0.2 installed, on Linux.