protected function getPossibleEmails()
    {
        $this->checkGit();
        $github_email = null;
        $github_email = str_replace(array("\r", "\n"), '', shell_exec('git config user.email'));

        if (filter_var($github_email, FILTER_VALIDATE_EMAIL)) {
            return [ $github_email ];
        } else {
            return [];
        }
    }