Kedudukan hukum kuasa sebagai bagian perjanjian pengikatan jual beli dalam hal terjadi kepailitan (studi kasus putusan Mahkamah Agung Nomor 261K/Pdt.Sus-Pailit/2016) = Legal status of the authority as part of the sale and purchase binding agreement in the event of bankruptcy (case study of supreme court decision number 261K/ Pdt.Sus-Pailit/2016)