code: func (m *Manager) GetPubKeyLocations(prefix string) ([]string, error) {
  	ensureLogger(m.Debug)
  	if prefix == "" {
  		return nil, fmt.Errorf("empty prefix")
  	}
  
  	kls, err := m.metaDiscoverPubKeyLocations(prefix)
  	if err != nil {
  		return nil, errwrap.Wrap(errors.New("prefix meta discovery error"), err)
  	}
  
  	if len(kls) == 0 {
  		return nil, fmt.Errorf("meta discovery on %s resulted in no keys", prefix)
  	}
  
  	return kls, nil
  }
docs: // GetPubKeyLocations discovers locations at prefix