Adding methods to "timetable" class

I am trying to add a method to built-in class "timetable". I was able to do it with other class like "double" by just adding "@double" directory and putting files there. Doesn't seem to work "timetable". Any ideas why is this the case and how to accomplish what I am trying to do?

Answer 1

[Walter Roberson]

>> dbtype timetable 1:2

1     classdef (Sealed) timetable < tabular

So timetable is a Sealed class, which means it does not permit any subclassing. That is likely interferring with you attempting to add additional methods.