As we know tuple is immutable. But at the same time it can contain mutable entities.
Say we have a next tuple:
x = (1, [1, 2])
Let's try to change first element:
x[0] = 10
----> 1 x[0] = 10
TypeError: 'tuple' object does not support item assignment
Yep. It is no wonder. Absolutely expected behavior.
Let's try to append an element to list in our tuple:
>>> x[1].append(3)
(1, [1, 2, 3])
No any errors since we mutate a mutable entity as a list. There is the same reference to list.
And now let's try to append via +=:
x[1] += [4]
----> 1 x[1] += [4]
TypeError: 'tuple' object does not support item assignment
>>> x
>>> Out[49]: (1, [1, 2, 3, 4])
Although there is TypeError value of our list have changed. I am a little bit confused.
What is the reason for such duality behavior?
