code: func normalizeAddresses(addrs []string, defaultPort string) []string {
  	for i, addr := range addrs {
  		addrs[i] = normalizeAddress(addr, defaultPort)
  	}
  
  	return removeDuplicateAddresses(addrs)
  }
docs: // normalizeAddresses returns a new slice with all the passed peer addresses
  // normalized with the given default port, and all duplicates removed.