package gw.plugin.billing enhancement PaymentPlanDataArrayEnhancement : T[] { reified property get InstallmentPlans(): InstallmentPlanData[] { return this.whereTypeIs(InstallmentPlanData) } reified property get ReportingPlans(): ReportingPlanData[] { return this.whereTypeIs(ReportingPlanData) } public function getByBillingId(id: String): T { return this.firstWhere(\p -> p.BillingId == id) } }