anchor.diff:  -spec(build_named_index([#dns_rr{}]) -> #{binary() => [#dns_rr{}]}).
   build_named_index(Records) ->
     NamedIndex = lists:foldl(fun (R, Idx) ->
  -    Name = erldns:normalize_name(R#dns_rr.name),
  -    maps:update_with(Name, fun (RR) -> [R | RR] end, [R], Idx)
  -  end, #{}, Records),
  +                               Name = erldns:normalize_name(R#dns_rr.name),
  +                               maps:update_with(Name, fun (RR) -> [R | RR] end, [R], Idx)
  +                           end, #{}, Records),
     maps:map(fun (_K, V) -> lists:reverse(V) end, NamedIndex).
   
   -spec(build_typed_index([#dns_rr{}]) -> #{dns:type() => [#dns_rr{}]}).
   build_typed_index(Records) ->
     TypedIndex = lists:foldl(fun (R, Idx) ->
  -    maps:update_with(R#dns_rr.type, fun (RR) -> [R | RR] end, [R], Idx)
  -  end, #{}, Records),
  +                               maps:update_with(R#dns_rr.type, fun (RR) -> [R | RR] end, [R], Idx)
  +                           end, #{}, Records),
     maps:map(fun (_K, V) -> lists:reverse(V) end, TypedIndex).
   
   -spec(sign_zone(erldns:zone()) -> erldns:zone()).
  
positive.code:     {ok, _Zone} ->
        lists:flatten(
          lists:foldl(
  	   fun(R, Records) ->
  			case R#dns_rr.data#dns_rrdata_rrsig.type_covered =/= TypeCovered of
  				true -> [R | Records];  
  				false -> [Records]
  			end
   	   end, [], get_records_by_name_and_type(Fqdn, ?DNS_TYPE_RRSIG_NUMBER))
  	 );
      _ ->
        []
    end.
  
negative.code: % Sign RRSet
  -spec(sign_rrset(binary(), [dns:rr()], [dns:rr()], [erldns:keyset()]) -> [dns:rr()]).
  sign_rrset(Name, Records, DnsKeyRRs, KeySets) ->
    % lager:debug("Signing RRSet for zone (name: ~p)", [Name]),
    KeyRRSigRecords = lists:flatten(lists:map(erldns_dnssec:key_rrset_signer(Name, DnsKeyRRs), KeySets)),
    ZoneRecords = get_zone_records(Name),
    RRSigRecords = rewrite_soa_rrsig_ttl(ZoneRecords, lists:flatten(lists:map(erldns_dnssec:zone_rrset_signer(Name, lists:filter(fun(RR) -> (RR#dns_rr.type =/= ?DNS_TYPE_DNSKEY) end, Records)), KeySets))),
    verify_rrset(DnsKeyRRs, KeyRRSigRecords),
    RRSigRecords.
  
  % Verify RRSet
  -spec(verify_rrset([dns:rr()], [dns:rr()]) -> boolean()).
  verify_rrset(DnsKeyRRs, KeyRRSigRecords) ->
  