public int DeleteManySchool(List <int> schoolIds)
 {
     try
     {
         int result = 0;
         foreach (int schoolId in schoolIds)
         {
             result += schoolRepository.DeleteSchool(schoolId);
             result += examRepository.DeleteAllExamBySchoolId(schoolId);
         }
         return(result);
     }
     catch (Exception ex)
     {
         throw ex;
     }
 }