You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: sanitize.go
    path of file: ./repos/wgnetwork/vendor/github.com/miekg/dns
    
    the code of the file until where you have to start completion: package dns

// Dedup removes identical RRs from rrs. It preserves the original ordering.
// The lowest TTL of any duplicates is used in the remaining one. Dedup modifies
// rrs.
// m is used to store the RRs temporary. If it is nil a new map will be allocated.
func Dedup(rrs []RR, m map[string]RR) []RR {

	if m == nil {
		m = make(map[string]RR)
	}
	// Save the keys, so we don't have t
    
func normalizedString(r RR) string {
	// A string Go DNS makes has: domainname<TAB>TTL<TAB>...
	b := []byte(r.String())

	// find the first non-escaped tab, then another, so we capture where the TTL lives.
	esc := false
	ttlStart, ttlEnd := 0, 0
	for i := 0; i < len(b) && ttlEnd == 0; i++ {
		switch {
		case b[i] == '\\':
			esc = !esc
		case b[i] == '\t' && !esc:
			if ttlStart == 0 {
				ttlStart = i
				continue
			}
			if ttlEnd == 0 {
				ttlEnd = i
			}
		case b[i] >= 'A' && b[i] <= 'Z' && !esc:
			b[i] += 32
		default:
			esc = false
		}
	}

	// remove TTL.
	copy(b[ttlStart:], b[ttlEnd:])
	cut := ttlEnd - ttlStart
	return string(b[:len(b)-cut])
}