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Date: Thu, 16 Aug 2012 09:07:58 -0700
From: Ethan Furman <ethan@stoneleaf.us>
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Xref: csiph.com comp.lang.python:27175

Hans Mulder wrote:
> On 8/08/12 04:14:01, Steven D'Aprano wrote:
>> NoneType raises an error if you try to create a second instance. bool
>> just returns one of the two singletons (doubletons?) again.
>>
>> py> type(None)()
>> Traceback (most recent call last):
>>   File "<stdin>", line 1, in <module>
>> TypeError: cannot create 'NoneType' instances
> 
> Why is that?

An oversight, and until a few months ago nobody had complained loud 
enough.  ;)


> Why doesn't it just return an existing instance of the type,
> like bool, int, str and other built-in non-mutable types do?

In 3.3 it now does.

~Ethan~