Kekuatan Hukum Perjanjian Pengikatan Jual Beli (PPJB) Atas Satuan Rumah Susun Antara Pembeli Dan Pengembang Berkaitan Dengan Resiko Pailit Terhadap Pengembang (Studi Kasus Pada PT. Broadbiz Asia) = The Force Of Binding Sale And Purchase Agreements (PPJB) Over The Units Of Flats Formed Between Buyers And Developers Associated With The Risk Of Bankruptcy Against The Developers (Case Study on PT Broadbiz Asia)