#NEWLINE# def diff( self , list1 , list2 ) : #NEWLINE# #INDENT# 'Returns the list of entries that are present in list1 but not in list2.\n\n    Args:\n      list1: A list of elements\n      list2: Another list of elements\n\n    Returns:\n      A list of elements unique to list1\n    ' #NEWLINE# return sorted ( ( set ( list1 ) - set ( list2 ) ) )