object identity and hashing

[castironpi at gmail.com]

> But this doesn't tell you anything about Python except that it's
> flexible enough to construct counter-intuitive classes.
>
> Everything you have been told is true for the normal cases you will come
> across in everyday usage. If you want to play in the obscure corners of
> the language that's fine, but don't try and treat them as mainstream.

Good point.