What's wrong with `is not None`?

[Jive Dadson]

Frans Englich wrote:
> 
> That's what PyChecker tells me, at least.
> 
> A line of:
> 
> if testReport is not None:
> 
> results in:
> 
> runner.py:587: Using is not None, may not always work
> 
> In what circumstances can `is not None` fail? How and why does it fail?
> 
> What is the equivalent expression which is more secure; `!= None`?

Yeah, that'll do it.

Incredibly, Microsoft has patented the "isnot" operator.  I kid you not.
They are amassing an incredible number of patents, many with no more
merit than the "isnot" one.  I'll leave it to your imagination as to
why.