code: function validateConfig(config) {
      // appId and versionId are not validated here since
      // not all operations require these to be present.
      // Validation of specific params are done in the
      // ServiceBase.js
      const { authoringKey, region } = config;
      const messageTail = `is missing from the configuration.\n\nDid you run ${chalk.cyan.bold('luis init')} yet?`;
  
      assert(typeof authoringKey === 'string', `The authoringKey  ${messageTail}`);
      assert(typeof region === 'string', `The region ${messageTail}`);
      assert(args.region == 'westus' || args.region == 'westeurope' || args.region == 'australiaeast' || args.region == 'virginia', `${args.region} is not a valid authoring region.  Valid values are [westus|westeurope|australiaeast|virginia]`);
  }
docs: Validates the config object to contain the
  fields necessary for endpoint calls.
  
  @param {*} config The config object to validate