protected function writeValidity($output, $message, $isValid = null) {
        if ($this->firstValidityWrite) {
            $output->writeln('');
            $this->firstValidityWrite = false;
        }

        if (is_bool($isValid)) {
            $message = sprintf(
                '%s - %s',
                $isValid ? '<fg=green>Valid</>' : '<fg=red>Invalid</>',
                $message
            );
        }

        $output->writeln($message);
    }