private function validateAdditionalItems(array $subject, array $schema): bool
    {
        $subject = \array_slice($subject, count($schema['items']));

        if (\is_bool($schema['additionalItems'])) {
            return $this->validateAdditionalItemsSchemaBoolean($subject, $schema);
        }
        if (\is_int(\array_keys($schema['additionalItems'])[0])) {
            return $this->validateAdditionalItemsSchemaArray($subject, $schema);
        }
        return $this->validateAdditionalItemsSchemaObject($subject, $schema);
    }