public function table(string $class_name, string $id_value = ''): self
    {
        if (preg_match(",\s,", $id_value)) {
            throw new DOMException("the id attribute's value must not contain whitespace (spaces, tabs etc.)");
        }
        $clone = clone $this;
        $clone->class_name = $class_name;
        $clone->id_value = $id_value;

        return $clone;
    }