Keabsahan perjanjian pengikatan jual beli berdasarkan akta kuasa menjual serta peran dan tanggung jawab notaris dalam pembuatan perjanjian pengikatan jual beli: studi putusan Mahkamah Agung Republik Indonesia Nomor 46 K/Pid/2017 = The validity of the sale and purchase binding agreement based on the deed of authorization to sell and the role and responsibility of notary in making the sale and purchase binding agreement: case study Supreme Court of RI Decision No. 46 K/Pid/2017