public function getGradeConversion($con = null) { include_once 'lib/model/om/BaseGradeConversionPeer.php'; if ($this->aGradeConversion === null && $this->grade_conversion_id !== null) { $this->aGradeConversion = GradeConversionPeer::retrieveByPK($this->grade_conversion_id, $con); } return $this->aGradeConversion; }