How to script modifying a body shape?

Hello,

I'm trying to write a very simple "random character" script, but I really don't know to script.

I have to do two things :

        - How to get existing shapes names for an object ?

        - How to set a shape on an object once I have my object and the shape name? ( something like: object.set_chape("Giselle_6_body", 0.75) ) ?

Thanks for help.