inspect the call stack

[bussiere bussiere]

i v'e got this :
    i've got toto.py :

    import titi
    def niwhom():
        pass

    and titi.py :

    def nipang():
         pass

    how can i know in titi.py that's it's toto.py that is calling titi.py
    and the path of toto ?

how can i inspect the call stack or an other way ?

Regards
Bussiere
Google Fan boy