code: async function challengeCreateFn(authz, challenge, keyAuthorization) {
      log('Triggered challengeCreateFn()');
  
      /* http-01 */
      if (challenge.type === 'http-01') {
          const filePath = `/var/www/html/.well-known/acme-challenge/${challenge.token}`;
          const fileContents = keyAuthorization;
  
          log(`Creating challenge response for ${authz.identifier.value} at path: ${filePath}`);
  
          /* Replace this */
          log(`Would write "${fileContents}" to path "${filePath}"`);
          // await fs.writeFile(filePath, fileContents);
      }
  
      /* dns-01 */
      else if (challenge.type === 'dns-01') {
          const dnsRecord = `_acme-challenge.${authz.identifier.value}`;
          const recordValue = keyAuthorization;
  
          log(`Creating TXT record for ${authz.identifier.value}: ${dnsRecord}`);
  
          /* Replace this */
          log(`Would create TXT record "${dnsRecord}" with value "${recordValue}"`);
          // await cloudflare.createRecord(dnsRecord, 'TXT', recordValue);
      }
  }
docs: Function used to satisfy an ACME challenge
  
  @param {object} authz Authorization object
  @param {object} challenge Selected challenge
  @param {string} keyAuthorization Authorization key
  @returns {Promise}