code: func dedupAddrs(addrs []ma.Multiaddr) (uniqueAddrs []ma.Multiaddr) {
  	exists := make(map[string]bool)
  	for _, addr := range addrs {
  		k := string(addr.Bytes())
  		if exists[k] {
  			continue
  		}
  		exists[k] = true
  		uniqueAddrs = append(uniqueAddrs, addr)
  	}
  	return uniqueAddrs
  }
docs: // mergeAddrs merges input address lists, leave only unique addresses