Habari\Comments::only PHP Method

    public function only($field, $index)
    {
        static $results = array();
        if (!isset($results[$field][$index])) {
            $result = array();
            foreach ($this as $comment) {
                if ($comment->{$field} == $index) {
                    $result[$comment->id] = $comment;
                }
            }
            $results[$field][$index] = new Comments($result);
        }
        return $results[$field][$index];
    }