code: func (ks *Keystore) DeleteTrustedKeyPrefix(prefix, fingerprint string) error {
  	acidentifier, err := types.NewACIdentifier(prefix)
  	if err != nil {
  		return err
  	}
  	return os.Remove(path.Join(ks.LocalPrefixPath, acidentifier.String(), fingerprint))
  }
docs: // DeleteTrustedKeyPrefix deletes the prefix trusted key identified by fingerprint.