def _keyUp(key):
    """Performs a keyboard key release (without the press down beforehand).

    Args:
      key (str): The key to be released up. The valid names are listed in
      pyautogui.KEY_NAMES.

    Returns:
      None
    """

    """
    Release a given character key. Also works with character keycodes as
    integers, but not keysyms.
    """
    if key not in keyboardMapping or keyboardMapping[key] is None:
        return

    if type(key) == int:
        keycode = key
    else:
        keycode = keyboardMapping[key]

    fake_input(_display, X.KeyRelease, keycode)
    _display.sync()
Performs a keyboard key release (without the press down beforehand).

    Args:
      key (str): The key to be released up. The valid names are listed in
      pyautogui.KEY_NAMES.

    Returns:
      None