code: def key_press_event(self, widget, event):
          
          # get keyname or keycode and translate to ginga standard
          # keyname =
          # keycode =
          keyname = ''  # self.transkey(keyname, keycode)
          self.logger.debug("key press event, key=%s" % (keyname))
          return self.make_ui_callback('key-press', keyname)
docs: Called when a key is pressed and the window has the focus.
          Adjust method signature as appropriate for callback.