>>> a = 2
>>> b = 2
>>> a is b
True
>>> a = -3
>>> b = -3
>>> a is b
True
>>> a = 257
>>> b = 257
>>> a is b
False
>>> 2 + 2
4
>>> import ctypes
>>> ctypes.memmove(id(2), id(3), object.__sizeof__(2))
94302108986496
>>> 2 + 2
6
>>>
>>> a = 2
>>> b = 2
>>> a is b
True
>>> a = -3
>>> b = -3
>>> a is b
True
>>> a = 257
>>> b = 257
>>> a is b
False
>>> 2 + 2
4
>>> import ctypes
>>> ctypes.memmove(id(2), id(3), object.__sizeof__(2))
94302108986496
>>> 2 + 2
6
>>>