gistfile1.txt

>>> def foo(a=[]):
  >     a.append(1)
  >     print(a)
  >     
<foo(a=...) from <stdin>>
   1        0 GET_LOCAL           0 (a, kwarg)) +a
            2 TEST_ARG            4 (to 9)
            5 MAKE_LIST           0
            7 SET_LOCAL_POP       0 (a, kwarg))

   2  >>    9 GET_LOCAL           0 (a, kwarg))
           11 GET_METHOD          0 'append'
           13 CONSTANT            1 1
           15 CALL_METHOD         1
           17 POP                   

   3       18 GET_GLOBAL          2 'print'
           20 GET_LOCAL           0 (a, kwarg))
           22 CALL                1
           24 POP                   
           25 NONE                   -a
           26 RETURN                
<<module>() from <stdin>>
   3        0 CLOSURE             1 <function foo> 
            2 DEFINE_GLOBAL       0 'foo'

   4        4 NONE                  
            5 RETURN                
>>> foo()
<<module>() from <stdin>>
   1        0 GET_GLOBAL          0 'foo'
            2 CALL                0
            4 RETURN                
[1]
>>> foo()
<<module>() from <stdin>>
   1        0 GET_GLOBAL          0 'foo'
            2 CALL                0
            4 RETURN                
[1]