Major While it seems to support many different kinds of collections of intervals and is therefore pretty powerful, it doesn't seem very easy to do the simple stuff - i.e. most people will likely do simple linear sequences most of the time. In the ASHRAE SPC201P FSGIM committee, while we are inheriting WS-Cal and are using it for the general case, we created a way to do this simple case directly. As I recall, I think that's the Sequence class which contains an ordered set of SimpleIntervals.