RW_Meta_Box::validate PHP Method

    protected function validate()
    {
        $nonce = (string) filter_input(INPUT_POST, "nonce_{$this->meta_box['id']}");
        return true !== $this->saved && (!defined('DOING_AUTOSAVE') || $this->meta_box['autosave']) && wp_verify_nonce($nonce, "rwmb-save-{$this->meta_box['id']}");
    }