public function getColumns($posts)
    {
        $columns = array();

        if (is_array($posts)) {
            foreach ($posts as $post) {
                $values = get_field('posts_list_column_titles', $post);

                if (is_array($values)) {
                    foreach ($values as $value) {
                        $columns[] = $value['column_header'];
                    }
                }
            }
        }

        return $columns;
    }