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

[Benjamin Peterson]

Michael Foord <fuzzyman at ...> writes:

> 
> 
> On 6 July 2011 17:55, Benjamin Peterson <benjamin <at> python.org> wrote:
> Michael Foord <fuzzyman <at> ...> writes:
> > It would feel cleaner to me if I could make FunctionTypes a set and use that
> as the second argument to isinstance.
> I just had a another thought about abritrary collections. It was explode loudly
> if you made an class.
> 
> 
> Could you rephrase please? I have no idea what this means. All the
best,Michael Foord 

Mm. I don't blame you. I'll speak code:

class Evil(type):
    def __iter__(self):
        return range(42)


class Accomplice(metaclass=Evil):
    pass

isinstance(12, Accomplice()) # boom if arbitrary iterables are allowed