public void addEvaluation(String courseID, String name,
String instructions, boolean commentsEnabled, Date start,
Date deadline, double timeZone, int gracePeriod)
throws EvaluationExistsException {
if (getEvaluation(courseID, name) != null) {
throw new EvaluationExistsException();
}
Evaluation evaluation = new Evaluation(courseID, name, instructions,
commentsEnabled, start, deadline, timeZone, gracePeriod);