Python list.append() vs list.extend()

append_extend.py

# append adds its argument as a single element to the end of a list.
# The length of the list itself will increase by one.
# extend iterates over its argument adding each element to the list, extending the list
my_list = [1, 2, 3]
my_list.append([4, 5, 6])
# [1, 2, 3, [4, 5, 6]]
my_list = [1, 2, 3]
my_list.extend(4, 5, 6])
# [1, 2, 3, 4, 5, 6]