[Python-ideas] Allow isinstance second argument to be a set of types

[Steven D'Aprano]

Michael Foord wrote:
> Hello all,
> 
> Occasionally I build up tuples of types for passing as the second argument
> to isinstance. I've noticed on occasions having duplicates, for example the
> following code is Python 2 & 3 compatible but results in a duplicate on one
> of them:
[...]
> It would feel cleaner to me if I could make FunctionTypes a set and use that
> as the second argument to isinstance. :-)


Does it matter if there is a duplicate entry?



-- 
Steven