public function SetProperty($DiscussionID, $Property, $ForceValue = NULL) {
      if ($ForceValue !== NULL) {
         $Value = $ForceValue;
      } else {
         $Value = '1';
         $Discussion = $this->GetID($DiscussionID);
         $Value = ($Discussion->$Property == '1' ? '0' : '1');
      }
      $this->SQL
         ->Update('Discussion')
         ->Set($Property, $Value)
         ->Where('DiscussionID', $DiscussionID)
         ->Put();
      
      return $Value;
   }