Caching tiles locally?

[Fabrice Delente <delentef gmail com>]

Hello,

I use libchamplain in python+GTK3 to create a small GPS viewer for the
tracks I run in my hometown. I'd like to cache the data for my town on
my computer, so that I don't have to reload the data from the web.
I've looked at the API but don't see how I can do that, can anybody
give me directions? Thanks.