private function appendCommandOptions(array $commandParts)
    {
        foreach ($this->options as $optionKey) {
            // Skip tab-width option because it's appended by default.
            if ($optionKey == 'tab-width') {
                continue;
            }

            $optionValue = $this->option($optionKey);
            if (!empty($optionValue)) {
                $commandParts[] = sprintf('--%s=%s', $optionKey, $optionValue);
            }
        }

        return $commandParts;
    }