public static function isChildOlsubjects($SubjectId, $ChildSubjectId)
 {
     $ischild = false;
     $obj_retResult = DAL_manageOlsubjects::getOlsubjectsListBySubjectId($ChildSubjectId);
     //get child node
     if ($obj_retResult->type == 1) {
         $arr_OlsubjectsList = $obj_retResult->data;
         $obj_Olsubjects = $arr_OlsubjectsList[0];
         $arrParentIds = explode(",", $obj_Olsubjects->Url);
         foreach ($arrParentIds as $OlsubjectsParentId) {
             if ($OlsubjectsParentId == $SubjectId) {
                 $ischild = true;
             }
         }
     }
     return $ischild;
 }