Within the document class or the main timeline (which IS the root), you could just do:
Code:
myDocClassFunction();
From other instances/classes you would still need to get a reference to the document instance to call that function.


By stateless, I mean that it does not keep any info around in variables between function calls. It should not have any modes set or things like that. This is not required, it's just good practice. If you do need state, then the class should not be static, you should get an instance to store in whatever scope you need it.

The reason to avoid storing state in a static class is that other stuff you might not plan on could alter that state. Say your convert utility was written in a stateful manner, where you'd have to set the to-unit and the from-unit, then call convert. Between calls to convert, another class might change the units, and mess up your values. If instead, you had function convert(from, to, value):Number, then each call would be completely independent of anything else that has happened to the class.