def key_up(self, key: Union[str, Key], blocking: bool = True) -> Union[None, FutureResult[None]]:
        """
        Shortcut for :py:meth:`send_input` but transforms specified key to perform a key "UP" only. Useful if the key
        was previously pressed down but not released.
        """
        if isinstance(key, str):
            key = Key(key_name=key)
        if blocking:
            self.send_input(key.UP, blocking=True)
            return None
        else:
            return self.send_input(key.UP, blocking=False)

        Shortcut for :py:meth:`send_input` but transforms specified key to perform a key "UP" only. Useful if the key
        was previously pressed down but not released.
        
ahk/_sync/engine.py