what happens when i append to a list python code example

Example 1: append object python

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

Example 2: extend in list python

subjects=["Maths","Science","Arts","Commerce"]
subjects_2=["Artificial intelligence","Statistics"]
subjects.extend(subjects_2)
print(subjects)  ## used to add more elements from other list

Example 3: append a list to another list as element

a = ['Jon', 'janni', 'Jannardhan']
b = ['28', '29', '30']
a.append(b)
print(a)
a.pop()
a.extend(b)
print(a)