FYI: using xyz is 0 only works due to implementation details of CPython, which uses the same object in memory for each number 0 to 256. If a number beyond 256 is calculated, a new Python int object is created for it

In [1]: a, b = 256, 256

In [2]: a, b, a is b
Out[2]: (256, 256, True)

In [3]: a -= 1; b -= 1

In [4]: a, b, a is b
Out[4]: (255, 255, True)

In [5]: a += 2; b += 2

In [6]: a, b, a is b
Out[6]: (257, 257, False)

But it was fun!