Question

Every now and then I come across code like this:

foo = Foo()
...
if foo.bar is not None and foo.bar.baz == 42:
   shiny_happy(...)

Which seems, well, unpythonic, to me.

In Objective-C, you can send messages to nil and get nil as the answer. I’ve always thought that’s quite handy. Of course it is possible to implement a Null pattern in Python, however judging from the results Google’s given me, it seems this is not very widely used. Why’s that?

Or even better—would it be a bad idea to let None.whatever return None instead of raising an exception?

Answer 1

PEP 336 – Make None Callable proposed a similar feature:

None should be a callable object that when called with any arguments
has no side effect and returns None.

The reason for why it was rejected was simply “It is considered a feature that None raises an error when called.”