Validation
constructor(uid: String, code: String?, name: String?, displayName: String?, created: Date?, lastUpdated: Date?, deleted: Boolean?, shortName: String?, displayShortName: String?, description: String?, displayDescription: String?, instruction: String?, importance: ValidationRuleImportance?, operator: ValidationRuleOperator?, periodType: PeriodType?, skipFormValidation: Boolean?, leftSide: ValidationRuleExpression, rightSide: ValidationRuleExpression, organisationUnitLevels: List<Int>)