async isNextMonthButtonFocused() {
        const buttonEl = (await $(this.rootElement).$$('button[data-id=button-icon-element]'))[1];
        // eslint-disable-next-line no-return-await
        return (await buttonEl.isExisting()) && (await buttonEl.isFocused());
    }
Returns true when the next month button element has focus.
@method
@returns {bool}