Get the Visa Type List. 

This is a listing of all of the Visa Type items. 

Each Visa Type item is represented by a TVity. The collection of Visa Type items is represented by a List of TVity. 

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

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

[WebMethod(Description = "Gets a list of all Visa Types")]
public TAuthVityList GetVisaTypeList(string sToken);