def _keyDown(key):
    """Performs a keyboard key press without the release. This will put that
    key in a held down state.

    NOTE: For some reason, this does not seem to cause key repeats like would
    happen if a keyboard key was held down on a text field.

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

    Returns:
      None
    """
    if key not in keyboardMapping or keyboardMapping[key] is None:
        return

    needsShift = pyautogui.isShiftCharacter(key)

    """
    # OLD CODE: The new code relies on having all keys be loaded in keyboardMapping from the start.
    if key in keyboardMapping.keys():
        vkCode = keyboardMapping[key]
    elif len(key) == 1:
        # note: I could use this case to update keyboardMapping to cache the VkKeyScan results, but I've decided not to just to make any possible bugs easier to reproduce.
        vkCode = ctypes.windll.user32.VkKeyScanW(ctypes.wintypes.WCHAR(key))
        if vkCode == -1:
            raise ValueError('There is no VK code for key "%s"' % (key))
        if vkCode > 0x100: # the vk code will be > 0x100 if it needs shift
            vkCode -= 0x100
            needsShift = True
    """
    mods, vkCode = divmod(keyboardMapping[key], 0x100)

    for apply_mod, vk_mod in [(mods & 4, 0x12), (mods & 2, 0x11),
        (mods & 1 or needsShift, 0x10)]: #HANKAKU not suported! mods & 8
        if apply_mod:
            ctypes.windll.user32.keybd_event(vk_mod, 0, 0, 0) #
    ctypes.windll.user32.keybd_event(vkCode, 0, 0, 0)
    for apply_mod, vk_mod in [(mods & 1 or needsShift, 0x10), (mods & 2, 0x11),
        (mods & 4, 0x12)]: #HANKAKU not suported! mods & 8
        if apply_mod:
            ctypes.windll.user32.keybd_event(vk_mod, 0, KEYEVENTF_KEYUP, 0)