Mastering-Python-2e-code_2/CH_05_functional_programming/T_00_intro.rst

>>> def add_value_functional(items, value):
...     return items + [value]

>>> items = [1, 2, 3]
>>> add_value_functional(items, 5)
[1, 2, 3, 5]
>>> items
[1, 2, 3]

>>> def add_value_regular(items, value):
...     items.append(value)
...     return items

>>> add_value_regular(items, 5)
[1, 2, 3, 5]
>>> items
[1, 2, 3, 5]