Python vs. Ruby

[Rob Renaud]

<lot snipped>
"John Roth" <johnroth at ameritech.net> wrote in message 
> Whether append() returns a *new* object or not is irrelevant to
> my arguement. The fact that it returns None is the wart.
> 
> John Roth

It's consistant, not a wart from my perspective.  If an object is
modified, it is not returned.

For every part of the (admittedly small) python library I know, that
is the case.  Returning None is a hint that the object is modified.

So then the question becomes, why don't append(), sort(), reverse()
return a new list and not modify the original?  Are mutable objects
themselves a wart on the langauge?