why to use append and not extend code example

Example 1: python append vs extend

my_list = [23, 11, 42, 24523]

# append will add it as if you're adding a new list to it
my_list.append([34523, 76979])
print(my_list)

# extend will go over each item in the new source list and add each
# element as part of the target list (my_list)
my_list.extend([12, 99])
print(my_list)

""" 
Output:
[23, 11, 42, 24523, [34523, 76979]]
[23, 11, 42, 24523, [34523, 76979], 12, 99]
"""

Example 2: how to append to a list of lists in python

list_of_Lists = [[1,2,3],['hello','world'],[True,False,None]]
list_of_Lists.append([1,'hello',True])
ouput = [[1, 2, 3], ['hello', 'world'], [True, False, None], [1, 'hello', True]]