How to use the reactxp.Input function in reactxp

componentWillUnmount() {
        super.componentWillUnmount();

        RX.Input.backButtonEvent.unsubscribe(this._onBack);
        RX.Input.keyUpEvent.unsubscribe(this._onKeyUp);
    }

componentDidMount() {
        super.componentDidMount();

        RX.Input.backButtonEvent.subscribe(this._onBack);
        RX.Input.keyUpEvent.subscribe(this._onKeyUp);
    }