>>> def a():
...     x=[1,2,3,4,5]
...     y=x[2]
...
>>> def b():
...     x=(1,2,3,4,5)
...     y=x[2]
...
>>> import dis
>>> dis.dis(a)
  2           0 LOAD_CONST               1 (1)
              3 LOAD_CONST               2 (2)
              6 LOAD_CONST               3 (3)
              9 LOAD_CONST               4 (4)
             12 LOAD_CONST               5 (5)
             15 BUILD_LIST               5
             18 STORE_FAST               0 (x)

  3          21 LOAD_FAST                0 (x)
             24 LOAD_CONST               2 (2)
             27 BINARY_SUBSCR
             28 STORE_FAST               1 (y)
             31 LOAD_CONST               0 (None)
             34 RETURN_VALUE
>>> dis.dis(b)
  2           0 LOAD_CONST               6 ((1, 2, 3, 4, 5))
              3 STORE_FAST               0 (x)

  3           6 LOAD_FAST                0 (x)
              9 LOAD_CONST               2 (2)
             12 BINARY_SUBSCR
             13 STORE_FAST               1 (y)
             16 LOAD_CONST               0 (None)
             19 RETURN_VALUE

$ python -m timeit "x=(1,2,3,4,5,6,7,8)"
10000000 loops, best of 3: 0.0388 usec per loop

$ python -m timeit "x=[1,2,3,4,5,6,7,8]"
1000000 loops, best of 3: 0.363 usec per loop

$ python -m timeit -s "x=(1,2,3,4,5,6,7,8)" "y=x[3]"
10000000 loops, best of 3: 0.0938 usec per loop

$ python -m timeit -s "x=[1,2,3,4,5,6,7,8]" "y=x[3]"
10000000 loops, best of 3: 0.0649 usec per loop

>>> from dis import dis

>>> dis(compile("(10, 'abc')", '', 'eval'))
  1           0 LOAD_CONST               2 ((10, 'abc'))
              3 RETURN_VALUE

>>> dis(compile("[10, 'abc']", '', 'eval'))
  1           0 LOAD_CONST               0 (10)
              3 LOAD_CONST               1 ('abc')
              6 BUILD_LIST               2
              9 RETURN_VALUE

typedef struct {
    Py_ssize_t ob_refcnt;
    struct _typeobject *ob_type;
    Py_ssize_t ob_size;
    PyObject *ob_item[2];     /* store a pointer to 10 and a pointer to 20 */
} PyTupleObject;

PyObject arr[2];              /* store a pointer to 10 and a pointer to 20 */

typedef struct {
    Py_ssize_t ob_refcnt;
    struct _typeobject *ob_type;
    Py_ssize_t ob_size;
    PyObject **ob_item = arr; /* store a pointer to the two-pointer array */
    Py_ssize_t allocated;
} PyListObject;