How to use the uiautomator2.exceptions.NullObjectExceptionError function in uiautomator2

if isinstance(
                err.data,
                six.string_types) and 'UiAutomation not connected' in err.data:
            err.__class__ = UiAutomationNotConnectedError
        elif err.message:
            if is_exception(err, 'uiautomator.UiObjectNotFoundException'):
                err.__class__ = UiObjectNotFoundError
            elif is_exception(err, 'android.support.test.uiautomator.StaleObjectException'):
                # StaleObjectException
                # https://developer.android.com/reference/android/support/test/uiautomator/StaleObjectException.html
                # A StaleObjectException exception is thrown when a UiObject2 is used after the underlying View has been destroyed.
                # In this case, it is necessary to call findObject(BySelector) to obtain a new UiObject2 instance.
                err.__class__ = StaleObjectExceptionError
            elif is_exception(err, 'java.lang.NullObjectException'):
                err.__class__ = NullObjectExceptionError
            elif is_exception(err, 'java.lang.NullPointerException'):
                err.__class__ = NullPointerExceptionError
        raise err