protected function parseOptions(array $options)
    {
        // Make sure to keep defined default attributes on the form.
        $options['attributes'] = array_merge($this->getAttributes(), $options['attributes']);

        // Define nonce default values if "method" attribute is set to "post".
        if (isset($options['attributes']['method']) && 'post' === strtolower($options['attributes']['method'])) {
            $options['nonce'] = $options['nonce'] ?? '_themosisnonce';
            $options['nonce_action'] = $options['nonce_action'] ?? 'form';
            $options['referer'] = $options['referer'] ?? true;
        }

        // Make sure a default theme is always defined. User cannot defined an
        // empty string for the form theme.
        if (! isset($this->options['theme'])) {
            $this->setTheme('themosis');
        }

        return $options;
    }