Expression can be simplified on list

[MRAB]

On 2016-09-29 09:14, Steven D'Aprano wrote:
> On Thursday 29 September 2016 16:47, Rustom Mody wrote:
>
>> On Thursday, September 15, 2016 at 1:43:05 AM UTC+5:30, Terry Reedy wrote:
> [...]
>>> Python make no such nonsense claim.  By default, Python objects are truthy.
>>>
>>>  >>> bool(object())
>>> True
>>>
>>> Because True is the default, object need not and at least in CPython
>>> does not have a __bool__ (or __len__) method.  Classes with no falsey
>>> objects, such as functions, generators, and codes, need not do anything
>>> either.  In the absence of an override function, the internal bool code
>>> returns True.
>>>
>> Not sure what you are trying to say Terry...
>> Your English suggests you disagree with me
>> Your example is exactly what I am saying; if a type has a behavior in which
>> all values are always True (true-ish) its a rather strange kind of
>> bool-nature.
>
> In what way do you think it is "rather strange"?
>
> This suggests that you believe that all types must have distinct truthy values
> and falsey values, or else that type's values shouldn't be usable in a truth
> context at all. Is that what you mean?
>
> My view is somewhat different. I see truthiness as an abstraction. Like all
> abstractions, it may leak -- I make no apologies for the fact that Python
> doesn't have syntactic support for Keene three-value logic or other multi-
> valued logics, nor do I make any apologies for the (hypothetical, rare) object
> which doesn't fit well into this truthy abstraction. All abstractions leak
> somewhere, and this abstraction is proven to work well in practice, not
> withstanding the rare glitch.
>
[snip]
When re.search or re.match succeed, they return a match object, which is 
truey; when they fail, then return None, which is falsey. That's convenient.