Python list element deletion question.

a = ["Aa", "Bb", "Cc"]
b = ["11", "22", "33"]
c = []

a.extend(b)
c.append(a)
c.append(a)

print("1", c)

del a[3:]

print("2", c)

After using the del function in the above code, 11, 22, 33 of the list elements ['Aa', 'Bb', 'Cc', '11', '22', '33'], ['Aa', 'Bb', 'Cc', '11', '22', '33'] are deleted.

I think it is right that there should be no change in the c list, but I wonder why it is printed as ['Aa', 'Bb', 'Cc'], ['Aa', 'Bb', 'Cc'].

If it happens inevitably in the above code,

del... I wonder if there is a way to output ['Aa', 'Bb', 'Cc', '11', '22', '33'], ['Aa', 'Bb', 'Cc', '11', '22', '33'] after the function.