checking if two things do not equal None

[Roy Smith]

In article <5337807b$0$29994$c3e8da3$5496439d at news.astraweb.com>,
 Steven D'Aprano <steve+comp.lang.python at pearwood.info> wrote:

> a is b is c is None

And we are all together.  See how they run like pigs from a gun, see how 
they fly.