A permutation on permutations

[arthur.siegel at rsmi.com]

Phil writes -

>BTW, if you change the 1st if statment to
>   if len(current) == len(source):
>you can get rid of the (done) variable.

But actually the 'done' variable is useful.  By setting
'done' to 2 as an argument -  if 'source'
 is 6 elements, I get back a list of the 4 element
permutations of the 6 elements - excluding reversals as
dups, of course.

Happens to be useful functionality for what I'm
playing with.

Thanks again.

Art