R. David Murray <rdmurray@bitdance.com> added the comment: The surprising thing is the behavior of NaN, which is *not equal* to itself. The statement about orderability says "...are ordered the same as their first unequal elements". This is explicit and unambiguous, there is no difference in this context between the number 1 and the singleton None, or the reflexivity enforced on NaN: all are equal to the corresponding element from the other sequence. The whole point of the paragraph is that *no order test is done until the first unequal element is encountered*. If we want to make this *more* explicit, I would suggest simply adding the following sentence after the first example in the original paragraph: "This means that reflexive elements that are otherwise unorderable (such as None and NaN) do not trigger a TypeError during a comparison." ---------- nosy: +r.david.murray _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue32118> _______________________________________