A demonstration of `copy.deepcopy` directly copying certain immutable types, instead of creating copies. This is in contrast to a literal copy-paste of the list, which will instantiate new PyObjects for ints outside the 0-256 range.

deepcopy-immutable-direct-copy.py

import copy

x = [257, 258, 259]
y = copy.deepcopy(x)
z = [257, 258, 259]

header = [('', 'x', 'deepcopy(x)', 'z')]
rows = [(i, id(i), id(j), id(k)) for i, j, k, in zip(x, y, z)]

for cols in header + rows:
    print '%10s%14s%14s%14s' % cols
    

output.pycon

Python 2.7.12 (default, Nov 19 2016, 06:48:10) 
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import copy
>>> 
>>> x = [257, 258, 259]
>>> y = copy.deepcopy(x)
>>> z = [257, 258, 259]
>>> 
>>> header = [('', 'x', 'deepcopy(x)', 'z')]
>>> rows = [(i, id(i), id(j), id(k)) for i, j, k, in zip(x, y, z)]
>>> 
>>> for cols in header + rows:
...     print '%10s%14s%14s%14s' % cols
... 
                       x   deepcopy(x)             z
       257      15592584      15592584      15592440
       258      15592560      15592560      15592416
       259      15592608      15592608      15592656