Why return None?

[Peter Hansen]

Martin DeMello wrote:

> It seems to be a fairly common pattern for an object-modifying method to
> return None - however, this is often quite inconvenient.

http://www.python.org/doc/faq/general.html#why-doesn-t-list-sort-return-the-sorted-list

(Not an answer to the general question you ask, unless you
extrapolate from the specific answer given there to the
more general case.)

-Peter