On Jan 16, 4:28 am, "Lambert, David W (S&T)" <Lamber... at Corning.com> wrote: > Although isinstance predates sets, the python history I recall is that > allowing tuples as second argument to isinstance happened at about the > same time as set type was builtin. isinstance 2nd arg as tuple of type info: 2.2 sets module: 2.3 set type: 2.4