code: async function _main([buildNumber, compareUrl = '', circleToken = '']) {
    try {
      if (!buildNumber || isNaN(buildNumber)) {
        throw new Error(
            'Missing or invalid arguments.\n' +
            'Expected: buildNumber (number), compareUrl? (string), circleToken? (string)');
      }
  
      if (!compareUrl) {
        compareUrl = await getCompareUrl(buildNumber, circleToken);
      }
  
      const commitRangeMatch = COMPARE_URL_RE.exec(compareUrl)
      const commitRange = commitRangeMatch ? commitRangeMatch[1] : '';
  
      console.log(commitRange);
    } catch (err) {
      console.error(err);
      process.exit(1);
    }
  }
docs: Helpers