Get the Class (or Instance) List for an Occurrence or Booking. 

In this context the term class means an instance where and when training occurs. (As in what occurs in a classroom). This is not to be confused with the notion of a class in software development. 

This is a listing of all Classes (or Instances) linked to an Occurrence or Booking. 

Each Class (or Instance) is represented by a TInst. The collection of Classes (or Instances) is represented by a List of TInst. 

A token is passed for authentication. If the authentication fails, or other errors occur, no classes (or instances) are returned. The result of the authentication is represented by a TAuthenticate object. 

Requires a valid registration key entry for the Short Courses feature. 

This function has security level "Unrestricted", and can be accessed by any authenticated user.

[WebMethod(Description = "Gets a list of classes (instances) within the occurrence with the specified ID")]
public TAuthInstList GetClassesForOccurrence(string sToken, int iID);