docs: 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
  
      if type(key) == int:
          fake_input(_display, X.KeyPress, key)
          _display.sync()
          return
  
      needsShift = pyautogui.isShiftCharacter(key)
      if needsShift:
          fake_input(_display, X.KeyPress, keyboardMapping['shift'])
  
      fake_input(_display, X.KeyPress, keyboardMapping[key])
  
      if needsShift:
          fake_input(_display, X.KeyRelease, keyboardMapping['shift'])
      _display.sync()