code: function bucketExists(aws, bucketName) {
    return aws.request('S3', 'listBuckets', {}).then(resp => {
      let exists = false;
      resp.Buckets.forEach(bucket => {
        if (bucket.Name === bucketName) {
          exists = true;
        }
      });
      return exists;
    });
  }
docs: Checks if an S3 bucket exists
  @param {Object} aws - AWS class
  @param {string} bucketName - Name of bucket to look for
  
  @returns {Promise<boolean>}