Hello I indeed also rely on your idea. My problem however is: is has to be non-intrusively in both ways.
In your example, it would indeed not break the old code which relies on myfunction but my problems is: I also do not want to change the code of the 'before' myfunction. so my problem in fact is: BEFORE: def myfunction(a,b): return (a+b) AFTER: def myfunction(a,b, op="add"): if (op == "add"): # some function which calls the old code for myfunction kind regards -- http://mail.python.org/mailman/listinfo/python-list