Implikasi hukum akta jual beli berdasarkan perjanjian pengikatan jual beli sebagai perjanjian simulasi (analisis atas putusan mahkamah agung no. 785 K/PDT/2012) = Legal impact of sale purchase deed based on sale purchase commitment agreement as a simulation agreement (analysis on supreme court decision no. 785 K/PDT/2012)