code: func ProjectFromBucket(bucket string) string {
  	// Buildbucket guarantees that buckets that start with "luci."
  	// have "luci.<project id>." prefix.
  	parts := strings.Split(bucket, ".")
  	if len(parts) >= 3 && parts[0] == "luci" {
  		return parts[1]
  	}
  	return ""
  }
docs: // ProjectFromBucket tries to retrieve project id from bucket name.
  // Returns "" on failure.