why () is () and [] is [] work in other way?

[Chris Angelico]

On Mon, Apr 23, 2012 at 5:43 AM, John Nagle <nagle at animats.com> wrote:
> Operator "is" should be be an error between immutables
> unless one is a built-in constant.  ("True" and "False"
> should be made hard constants, like "None". You can't assign
> to None, but you can assign to True, usually with
> unwanted results.  It's not clear why True and False
> weren't locked down when None was.)

Only in Python 2. In Python 3:

>>> True=3
SyntaxError: assignment to keyword

ChrisA