function override???

[Arinte]

I am defining a python callback for my embedded app, but I want the script
writer to override my function.  So, basically what I want is a function
prototype.  Ex. here is what I am thinking.

;---fprot.py
def overrideme(self, str, someint)

;--fimp.py
import fprot   #I know this ain't right.
                          # I don't know how to import from other python
scripts yet.  Enlighten me?

def overrideme(self, str, someint)
    do_some_junk()