Oops: there was as indentation problem in one of the examples in the docs above. The 'just finished y' example should read: for x in (1,2,3,4): for y in (5,6): for z in (7,8,9,10): pars = (x,y,z) print 'Just finished y' Not: for x in (1,2,3,4): for y in (5,6): for z in (7,8,9,10): pars = (x,y,z) print 'Just finished y' JDH