On , I learnt ...

You can arbitrarily chain Python comparison operations

Which explains why:

>>> False == False in [False]

This odd looking expression is equivalent to (False == False) and (False in [False]), hence why it evaluates to True.

And since there’s no limit to how many comparisons can be chained together, this kind of thing is legal syntax:

>>> False is False == False in [False] in [[False]] not in [False]

See the Python docs on comparisons for more details.