Real-world use cases for map's None fill-in feature?

[Raymond Hettinger]

> Alternately, the need can be met with existing tools by pre-padding the
> iterator with enough extra values to fill any holes:
>
>     it = chain(iterable, repeat('', group_size-1))
>     result = izip_longest(*[it]*group_size)

Typo:  That should be izip() instead of izip_longest()