src/Responder/ChainedResponder.php
protected function assertValid(array $classes)
    {
        parent::assertValid($classes);

        foreach ($classes as $responder) {
            if (!is_subclass_of($responder, ResponderInterface::class)) {
                throw ResponderException::invalidClass($responder);
            }
        }
    }
protected function assertValid(array $classes)
    {
        parent::assertValid($classes);

        foreach ($classes as $responder) {
            if (!is_subclass_of($responder, ResponderInterface::class)) {
                throw ResponderException::invalidClass($responder);
            }
        }
    }
@inheritDoc

@throws ResponderException
If $classes does not implement the correct interface.