def test_labeller():
 assert (labeller(2) == ['q_1', 'q_0'])
 assert (labeller(3, 'j') == ['j_2', 'j_1', 'j_0'])

def test_labeller ( ) : assert ( labeller ( 2 ) == [ 'q_1' , 'q_0' ] ) assert ( labeller ( 3 , 'j' ) == [ 'j_2' , 'j_1' , 'j_0' ] )
test the labeller utility .