Kedudukan akta kuasa menjual dalam perjanjian pengikatan jual beli belum lunas untuk melaksanakan pembuatan akta jual beli: studi kasus putusan Pengadilan Tinggi DKI Jakarta nomor 758/PDT/2018/PT.DKI = The authority of deed of power of attorney in unsettled binding sale and purchase agreements to carry out creation of purchase deed registered: case study in a verdict of DKI Jakarta High Court number 758/PDT/2018/PT.DKI