private function setAdditionalItems($specification)
    {
        if (is_bool($specification)) {
            $this->additionalItems = $specification;
        } elseif ($specification instanceof ValidatorAnnotation) {
            $this->additionalItems = $this->createValidatorInstanceFromAnnotation(
                $specification
            );
        } else {
            throw new UnspecifiedValidatorException(
                'The validator is being initialized without a valid validator Annotation'
            );
        }
    }