Where to import modules?

[JCM]

Peter Hansen <peter at engcorp.com> wrote:
...

> Basically doing this is an optimization, and you shouldn't be optimizing
> before the program is working, and you shouldn't be optimizing without
> a real need for it.  (That is, just because it's a little faster doesn't
> mean it's worth doing.)

Aside from being an optimization, it's also good for documentation.
If you see an import at the top of a file it might not be immediately
clear how or why the module is being used.  It's similar reasoning to
why you might define variables in the narrowest scope posible.