code: func GetHash(namespace string) crypto.Hash {
  	if strings.HasPrefix(namespace, "sha256-") {
  		return crypto.SHA256
  	}
  	if strings.HasPrefix(namespace, "sha512-") {
  		return crypto.SHA512
  	}
  	return crypto.SHA1
  }
docs: // GetHash returns a fresh instance of the hashing algorithm to be used to
  // calculate the HexDigest.
  //
  // A prefix of "sha256-" and "sha512-" respectively returns a sha-256 and
  // sha-512 instance. Otherwise a sha-1 instance is returned.