examples/lists/append.py
from __future__ import print_function

letters = ['a', 'b', 'c', 'd']
print(letters)  # ['a', 'b', 'c', 'd']

letters.append('z')
print(letters)  # ['a', 'b', 'c', 'd', 'z']


print(letters.append('q'))  # None
print(letters) # ['a', 'b', 'c', 'd', 'z', 'q']

The same as a[len(a):] = [x]