On Sat, Nov 16, 2013 at 09:44:13AM -0800, Christopher Smith wrote:
>    I believe you noted above that
>    if the expression was previously unevaluated, an error was raised when you
>    try to convert to bool (or at least that's what happens in the current
>    master).

This only happens with the current master (and not included
with any release).  So, I think this code was written without
any assumption that error should be raised here or something like this.

>    So I think we need to raise an error for the case
>    of None. def conservative_bool(arg): if arg not in (True, False): raise
>    ValueError('argument is not True or False') return bool(arg)

Ok.