Guide to the python interp. source?

[Tim Gahnström /Bladerman]

"Terry Reedy" <tjreedy at udel.edu>
> > Things I want to change is for example, everything should be "call
> > refferense",
>
> It already is, which is why functions can mutate mutable objects.
> (This surprises some beginners.)  Of course, for immutables (numbers,
> strings, tuples), there is no semantic difference between reference
> and value passing except for reduced memory usage.

I want to make all variables mutable. When you want to make functions like
inc(x) where inc is supposed to increase the value of x by one. How is that
done in Python?
That is my view of CBR, maybe that is not the correct definition and I don't
need CBR.

Tim