code: function (err, results) {
      err && console.error(err);
  
      results.forEach(function (result) {
          var failures = result.run.failures;
  
          console.info(failures.length ? JSON.stringify(failures.failures, null, 2) :
              `${result.collection.name} ran successfully.`);
      });
  }
docs: The
  
  @param {?Error} err - An Error instance / null that determines whether or not the parallel collection run
  succeeded.
  @param {Array} results - An array of collection run summary objects.