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 {subscriptionKey} = config;
      const messageTail = `is missing from the configuration.\n\nDid you run ${chalk.cyan.bold('qnamaker init')} yet?`;
      assert(typeof subscriptionKey === 'string', `The subscriptionKey ${messageTail}`);
  }
docs: Validates the config object to contain the
  fields necessary for endpoint calls.
  
  @param {*} config The config object to validate