Initialises the underlying PApplet and creates a frame ( using ``create_frame`` if
        required ) to display it in.

def run_sketch(self):
        """
        Initialises the underlying PApplet and creates a frame ( using ``create_frame`` if
        required ) to display it in.

        """
        Sketch.instance = self
        self.init()
        frame = self.create_frame()
        if frame:
            frame.add(self)
            frame.pack()
            frame.visible = 1