What is the difference between Python's list methods append and extend?

What's the difference between the list methods append() and extend()?

.append() appends a single object at the end of the list:

>>> x = [1, 2, 3]
>>> x.append([4, 5])
>>> print(x)
[1, 2, 3, [4, 5]]

.extend() appends multiple objects that are taken from inside the specified iterable:

>>> x = [1, 2, 3]
>>> x.extend([4, 5])
>>> print(x)
[1, 2, 3, 4, 5]

Stack Overflow Q#252703, score: 5929