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Date: Fri, 21 Nov 2014 18:03:49 +1100
Subject: Re: Infinitely nested containers
From: Chris Angelico <rosuav@gmail.com>
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Xref: csiph.com comp.lang.python:81175

On Fri, Nov 21, 2014 at 4:54 PM, Gill Shen <gillarete@gmail.com> wrote:
> How is this behavior implemented under the hood? And why is this allowed at all? Is it just a curiosity or can you do something useful with it?

Simple: The list contains itself. When you dereference the list, you
get back the original list. It does have value; you just have to be
careful of any recursive operation like printing it out - the repr()
for a list carefully checks for this.

ChrisA