public static function addStudentContact($con, $studentId, StudentContact $contact)
 {
     try {
         //echo "thiss";
         $sql = $con->prepare("INSERT INTO studentcontact VALUES (?,?)");
         $cont = $contact->getContactNo();
         //$cont="222";
         //echo $cont;
         $sql->bind_param("ss", $studentId, $cont);
         if ($sql->execute() == TRUE) {
             return true;
         } else {
             return false;
         }
     } catch (Exception $w) {
         return false;
     }
 }