Python 2.7.3 (default, Mar 13 2014, 11:03:55) 
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import dis
>>> def foo():
...     useless = 'this is useless'
...     return None
... 
>>> dis.dis(foo)
  2           0 LOAD_CONST               1 ('this is useless')
              3 STORE_FAST               0 (useless)

  3           6 LOAD_CONST               0 (None)
              9 RETURN_VALUE