Comment by squeaky-clean

I wrote a blog post about this in the past. It's really fun going through the oddities of the language like this.

It caches small integers, but also literals used in the same interpreter context (I'm probably getting that last term wrong). You'll get different results if you run these in from the shell as opposed to executing a script, try it out!

Here's a fun example

    >>> x = 256; x is 256
    True
    >>> x = 257; x is 257
    True
    >>> x = 257
    >>> x is 257
    False
    >>> def wat():
    ...   x = 500
    ...   return x is 500
    >>> wat()
    True