fixing position of random distractors in env 

Hi thanks for the amazing project. Can anyone tell me how can I fix the position of objects ( random distractors ) in goto levels of babyai env. I've tried making changes to add_distractors function in roomgrid.py file but it breaks the code. Do I need to make changes to other file? Sorry I'm a newbie in this project, any help would be much appreciated :) Thanks  
