Perlindungan hukum bagi notaris yang menahan sertipikat demi menjaga kepentingan para pihak dalam pengikatan jual beli: analisis putusan Pengadilan Negeri Bukit Tinggi nomor 53/PID.B/2017/PN.BKT = Legal protection for notaries that hold the statute for safeguarding the interests of parties in binding of buying selling: analysis of the decision of Bukit Tinggi court number 53/ PID.B/ 2017/ PN.BKT