Problem when using it as an inline widget in Admin

[tanwirahmad]

I have recently encountered a problem with the widget when it is used as an inline widget in Admin. The problem is that the django was saving a new record for the inline form containing the widget even if you do not enter any value in that form.

Django 2.2

Workaround: in the value_from_datadict function, we should return a list of None, the IF condition should be like the following and we should return None on ValueError expection:

        if days == 0 and hours == 0 and minutes == 0 and seconds == 0:
            return None

        try:
            D = timedelta(
                days=int(days),
                hours=int(hours),
                minutes=int(minutes),
                seconds=int(seconds)
            )
        except ValueError:
            return None
        else:
            return str(D)