public function buildSlug(string $attribute, array $config, bool $force = null)
    {
        $slug = $this->model->getAttribute($attribute);

        if ($force || $this->needsSlugging($attribute, $config)) {
            $source = $this->getSlugSource($config['source']);

            if ($source || is_numeric($source)) {
                $slug = $this->generateSlug($source, $config, $attribute);
                $slug = $this->validateSlug($slug, $config, $attribute);
                $slug = $this->makeSlugUnique($slug, $config, $attribute);
            }
        }

        return $slug;
    }