[Python-Dev] Add a "transformdict" to collections

[Andrea Corbellini]

On Tue, Sep 10, 2013 at 11:28 AM, Antoine Pitrou <solipsis at pitrou.net> wrote:
> Therefore I propose adding the general pattern. Simple example:
>
>    >>> d = transformdict(str.lower)
>    >>> d['Foo'] = 5
>    >>> d['foo']
>    5
>    >>> d['FOO']
>    5
>    >>> list(d)
>    ['Foo']
>
> (case-insensitive but case-preserving, as the best filesystems are ;-))

Just a nitpick: if this example (or a similar one) gets into the
documentation, it would be better to replace str.lower() with
str.casefold().