def test_append_one() -> None:
"""Test LinkedList.append on a list of length 1."""
lst = LinkedList()
lst._first = _Node(1)
lst.append(2)
assert lst._first.next.item == 2
def test_append_empty() -> None:
"""Test LinkedList.append on an empty list."""
lst = LinkedList()
lst.append(1)
assert lst._first.item == 1