Is there any reason why collections.abc.[Sequence|MutableSequence] do
not have "__eq__" for free?

I was writing some tests now and was caught by surprise there.

(chcking the docs, if my custom MutbaleSequence also
inherits from "collections.abc.Set" I will have working "__eq__" - and "__ne__", methods
but also weirdly behaved "__le__" and cousins as a side efffect  - weird enough
I think i will just hand-write the "__eq__")

While theoretically adding "__eq__"  and "__ne__" _could_ hab
backward compatibility issues, I think it is more probable it would
actually fix some undetected bugs i a couple projets, as the default __eq__ is
an identity comparison (is). 

Anyway, maybe there is a reason it is not a given. Any thoughts?