Return value of an assignment statement?

[John Henry]

On Feb 23, 2:59 am, Jeff Schwab <j... at schwabcenter.com> wrote:
> Dennis Lee Bieber wrote:
> > On Fri, 22 Feb 2008 11:23:27 -0800, Jeff Schwab <j... at schwabcenter.com>
> > declaimed the following in comp.lang.python:
>
> >> I'm about through with this discussion, but FWIW, this is a real gotcha
> >> for me and many others.  This is a case where Python does not do what
> >> many programmers expect, and it at least takes some getting used-to.
>
> >    As opposed to the twice monthly shocked newbie discovering that a
> > mutable as a function default doesn't reset on the next invocation?
>
> >    In that aspect, it all comes down to the difference between mutables
> > and immutables in Python.
>
> You know what's illuminating the discussion?  Everybody thinks they
> understand this issue, but the explanations are contradictory.  It seems
> like half the folks think this is an issue of mutability vs.
> immutability, and the other half believe that has nothing to do with it.

You mean like this:  :=)

def invoke_some_fct(parent):
   y = parent.x
   try:
      y += [ 'world' ]
   except:
      y += ( 'world', )
   print y, parent.x

class abc:
   def __init__(self):
      self.x=[ 'hello' ]
      invoke_some_fct(self)
      print self.x
      self.x=( 'hello', )
      invoke_some_fct(self)
      print self.x

hw = abc()