def refresh_psd(self, z=None):
        if self.need_refresh:
            try:
                self.canvas.draw()
                self.need_refresh = False
            except IndexError as err_idx:
                print("Warning:", err_idx)
        self.tk_root.after(2000, self.refresh_psd)
redraw the graphic PSD plot if needed i.e.new data have been given to get_psd
dataset/ETHPy150Open ericgibert/supersid/supersid/tksidviewer.py/tkSidViewer.refresh_psd