Does 'is not None' serve any purpose here?

Question

I was surprised to discover that "X in Y is not None" does not throw an exception. I can't figure out how Python actually interprets this. What value does "is not None" operate on? Does it serve any purpose here?

>>> "asdf" in {} is not None
False
>>> 
>>> "asdf" in {"asdf": 1} is not None
True
>>> 

Answer 1

Python comparison chaining strikes again.

According to the same rules that says that 1 < 2 < 3 is equivalent to 1 < 2 and 2 < 3, these expressions:

"asdf" in {} is not None
"asdf" in {"asdf": 1} is not None

Are equivalent to:

"asdf" in {} and {} is not None
"asdf" in {"asdf": 1} and {"asdf": 1} is not None