How do you draw in gtkD? Simple example overriding Widget.draw() doesn't compile.

[Enjoys Math via Digitalmars-d-learn]

import gtk.MainWindow;
import gtk.Main;
import gtk.DrawingArea;
import cairo.Context;
import std.stdio;
void main(string[] args) {
    Main.init(args);
    auto win = new MainWindow("Hello World");
    win.setDefaultSize(200, 100);
    win.add(new MyDrawingArea());
    win.showAll();
    Main.run();
}

class MyDrawingArea : DrawingArea {
        override bool draw(Context cairo) {
                writeln("Hello");
                return true;
        }
}

Error:
Error: function main.MyDrawingArea.draw does not override any 
function, did you mean to override 'gtk.Widget.Widget.draw'?