code: function (keycode, down) {
          let _that = this[PRIVATE];
          if (_that.initialized() && _that.running()) {
              _that.gameboy.JoyPadEvent(keycode, down);
          }
      }
docs: /*
  Presses or releases a key
  - note that in the gameboy core, a key will stay pressed until it has been explicitly released.
  - will do nothing if the emulator is running
  
  @param keycode 1-8 number of the key to press (see Interface.KEYCODES)
  @param `true` to press key, `false` to release