If you know 0 <= shift <= margin, concatenating two ranges is slightly
more elegant (though perhaps not faster):
for i in range(shift) + range(shift+1, margin):
...
--Guido van Rossum, CWI, Amsterdam <Guido.van.Rossum@cwi.nl>
URL: <http://www.cwi.nl/cwi/people/Guido.van.Rossum.html>