As a toy problem, I tried to come up with objects `a, b` such that

```
type(a) == type(b) == int # True
a + 1 == b + 1 == 1       # True
a is b                    # False

```

It seems that `deepcopy`falls back on `_deepcopy_atomic`, as discussed [here](https://stackoverflow.com/questions/31621997/why-deepcopy-of-list-of-integers-returns-the-same-integers-in-memory).

Is it possible to create a copy of a small int in Python?