Default Value

[Roy Smith]

In article 
<447dd1c6-1bb2-4276-a109-78d7a067b442 at d8g2000pbe.googlegroups.com>,
 rusi <rustompmody at gmail.com> wrote:

> > > def f(a, L=[]):
> > >     L.append(a)
> > >     return L

> Every language has gotchas. This is one of python's.

One of our pre-interview screening questions for Python programmers at 
Songza is about this.  I haven't been keeping careful statistics, but 
I'd guess only about 50% of the candidates get this right.