Why is the value of a Checkbox forced to None?

[ljean]

The _format_value of a CheckBoxInput returns None if value is valid (True or False) .

See Line 446

def _format_value(self, value):
        if value in ('', True, False, None):
            value = None
        else:
            value = force_text(value)
        return value

Why don't keep the value as it is rather than returning None? I think this cause a different behavior from other field types.

In my case, it caused a bug when upgrading an application and it was very difficult to find.

Thanks for explaining the reason.

Best luc