Gets a list of occurrences that an employer is enrolled in, and that overlap a date range. 

After obtaining an occurrence, the employer's employees enrolled into that occurrence can be obtained by using the GetEmployeeEnrolmentsForEmployerEnrolment function. 

Each occurrence is represented by a TOccu. The list of occurrences is represented by a List of TOccu in the OccuList property in the returned TAuthOccuList. 

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

Requires a valid registration key entry for the Bookings feature. 

This function has security level "Protected", and can only be accessed by users that have explicitly been granted permission to the API.

[WebMethod(Description = "Gets a list of occurrences overlapping a date range that an employer is enrolled in")]
public TAuthOccuList GetOccurrencesForEmployer(string token, string employerIdentifier, DateTime startDate, DateTime endDate);