public string Save(StudentResult studentResult)
 {
     if (aStudentResultGateway.CheckResultOfSameCourseBySameStudent(studentResult))
     {
         return("This course's result is saved for the same student");
     }
     else
     {
         int rowAffected = aStudentResultGateway.Save(studentResult);
         if (rowAffected > 0)
         {
             return("Saved Successfully");
         }
         return("Saving Failed");
     }
 }