[Python] Hints about a script that read ftp contents ....

I have read ftpmirror.py but I can' manage to do what I want : I'd like
a script that read ftp directories recursively (ident if a file or a
directory) and puts all pdf's documents in a list.

Has anyone could give me an example of a function that read contents and
make the difference between files and directory.

Thanks for reading.

Conatic