human
Here's a good function header given the following:
I wrote the below code

    class UnmodifiedIsInstance(type, ):
        if ((sys.version_info[0] == 2) and (sys.version_info[1] <= 6)):
            @classmethod
            def __instancecheck__(cls, instance):
                if (cls.__name__ in (str(base.__name__) for base in bases)):
                    return isinstance(instance, bases)
                subclass = getattr(instance, '__class__', None)
                subtype = type(instance)
                instance_type = getattr(abc, '_InstanceType', None)
                if (not instance_type):
                    class test_object:
                        pass
                    instance_type = type(test_object)
                if (subtype is instance_type):
                    subtype = subclass
                if ((subtype is subclass) or (subclass is None)):
                    return cls.__subclasscheck__(subtype)
                return (cls.__subclasscheck__(subclass) or cls.__subclasscheck__(subtype))
        else:
            @classmethod
            def __instancecheck__(cls, instance):
                if (cls.__name__ in (str(base.__name__) for base in bases)):
                    return isinstance(instance, bases)
                return type.__instancecheck__(cls, instance)
    return with_metaclass(UnmodifiedIsInstance, *bases)

What's a good function header?
assistant
#Here's a good function header.

def unmodified_isinstance(*bases):