Keabsahan pelaksanaan lelang hak tanggungan yang dieksekusi langsung oleh bank (studi kasus putusan pengadilan negeri purbalingga nomor 01/Pdt.G/2013/Pn.Pbg, putusan banding pengadilan tinggi semarang nomor 482/Pdt/2013/Pt.smg dan putusan kasasi mahkamah agung nomor 1426k/Pdt/2014) = The validity of mortgage auction right directly executed by the bank (the analysis of Purbalingga district court decision 01/Pdt.G/2013/Pn.Pbg, semarang high court decision no 482/Pdt/2013/Pt.smg and supreme court decision no.1426k/Pdt /2014)