tuple([1, 2, [10]])+= [20, 30]

class Tuple(tuple):
    def __setitem__(self, key, value):
        print('tuple setitem', key, value)
        super().__setitem__(key, value)

    def __getitem__(self, item):
        print('tuple getitem', item)
        return super().__getitem__(item)


class List(list):
    def __iadd__(self, other):
        print('list iadd', other)
        super().__iadd__(other)
        print('list state: %s' % self)
        return self


x = Tuple([1, 2, List([10])])
print('x = (1, 2, [10])')

try:
    print('x[2] += [20, 30]...')
    x[2] += List([20, 30])
finally:
    print('Finally:', x)

# $ python tst.py
# x = (1, 2, [10])
# x[2] += [20, 30]...
# tuple getitem 2
# list iadd [20, 30]
# list state: [10, 20, 30]
# tuple setitem 2 [10, 20, 30]
# Finally: (1, 2, [10, 20, 30])
# Traceback (most recent call last):
#   File "tst.py", line 24, in <module>
#     x[2] += List([20, 30])
#   File "tst.py", line 4, in __setitem__
#     super().__setitem__(key, value)
# AttributeError: 'super' object has no attribute '__setitem__'