@Override
 public boolean anyClassThisSchoolYear(SchoolYear schoolYear) {
   return ClassSchedule.count(
           ClassSchedule.class, "semester = ?", new String[] {schoolYear.toString()})
       > 0;
 }
 @Override
 public List<ClassSchedule> findBySchoolYear(SchoolYear schoolYear) {
   return Lists.newArrayList(
       ClassSchedule.find(ClassSchedule.class, "semester = ?", schoolYear.toString()));
 }