Vasily Galkin authored Jan 08, 2019 and Kai Willadsen committed Jan 09, 2019

It looks that when init_template lambda attaching
was changed from class to instance in
pygobject@05c3b8dc
it argument list should change too.
I tested with printfs that when if it is called for class attaching
it receives self as "s", and for instance attaching - no arguments

This change fixes "missing 1 required positional argument: 's'" exception

After that meld opens but with empty window.
It looks to be related to the fact that MeldWindow tried to call
MeldWindow.init_template class method
resulting in second-time call of actual method,
since only instance method was replaced to empty in first call,
not the class one
(I think that the first call is from "newer" python-gi 3.30.4-1
and second call from meld itself)

Changing this to instance method solves this problem,
however I didn't tested on older python-gi

Digging a bit more, I found that the "Format as patch" dialog UI
- the 3-pane radiobuttons and reversing checkbox doesn't work.
The checkbox can be fixed by a simple addition of @Template.Callback()
but the radiobuttons don't