Bizarre method keyword-arg bug.

[Robert Brown]

Steven D'Aprano <steve at REMOVE-THIS-cybersource.com.au> writes:
> On Wed, 20 Aug 2008 13:09:21 -0400, Robert Brown wrote:
>
>> In any case, chances are high that Lisp's way of handling default
>> arguments would have been changed had it been shown to cause performance
>> problems.
>
> But nobody is suggesting that it would cause performance problems in 
> *Lisp*. It might, or it might not. Who cares? We're not talking about 
> Lisp, we're talking about *Python*, and evaluating default arguments 
> every time the function is called would certainly cause a performance hit 
> in Python.

Please explain why it's a performance problem for Python but not for other
languages.