[Python-3000] Minor problem with ABCMeta?

[Andrew McNamara]

The __subclasscheck__ method of ABCMeta contains the following code:

        # Check if it's a subclass of a registered class (recursive)
        for rcls in cls._abc_registry:
            if issubclass(subclass, rcls):
                cls._abc_registry.add(subclass)
                return True

It looks to me like this code will result in an unnecessary call to
cls._abc_registry.add() in the case that "subclass" is already in
cls._abc_registry. It looks like the code should be preceded with
something like:

        if subclass in cls._abc_registry:
            return True

-- 
Andrew McNamara, Senior Developer, Object Craft
http://www.object-craft.com.au/