Annoying behaviour of the != operator

[Peter Hansen]

Fredrik Lundh wrote:
> for a number of situations where __ne__ cannot be derived from __eq__,
> see:
> 
>     http://www.python.org/peps/pep-0207.html

That "number" being "one"?

I can see only one comment that seems to describe that situation, where 
it refers to "IEEE 754 floating point numbers do not satisfy [== being 
the complement of !=]".

(Though that may be justification enough for the feature...)

-Peter