There is no difference on Python 3: >>> dis.dis(foo) 2 0 SETUP_LOOP 3 (to 6) 3 >> 3 JUMP_ABSOLUTE 3

There is no difference on Python 3: >>> dis.dis(foo) 2 0 SETUP_LOOP 3 (to 6) 3 >> 3 JUMP_ABSOLUTE 3 >> 6 LOAD_CONST 0 (None) 9 RETURN_VALUE >>> dis.dis(bar) 2 0 SETUP_LOOP 3 (to 6) 3 >> 3 JUMP_ABSOLUTE 3 >> 6 LOAD_CONST 0 (None) 9 RETURN_VALUE