#NEWLINE# def test_performers( self ) : #NEWLINE# #INDENT# artists = [ Artist ( name = 'name1' ) , Artist ( name = 'name2' ) ] #NEWLINE# track = Track ( performers = artists ) #NEWLINE# self . assertEqual ( set ( track . performers ) , set ( artists ) ) #NEWLINE# with self . assertRaises ( AttributeError ) : #NEWLINE# #INDENT# track . performers = None