anchor.diff:      decode_nxt_bmp(Offset + 1, Rest, Types).
   
   encode_nxt_bmp(UnsortedTypes) when is_list(UnsortedTypes) ->
  -    Types = unique_list([int_or_badarg(fun type_to_int/1, Type)
  +    Types = lists:usort([int_or_badarg(fun type_to_int/1, Type)
   			 || Type <- UnsortedTypes]),
       encode_nxt_bmp(0, Types, <<>>).
   
  
positive.code: 
  round_pow(N, E) -> round(math:pow(N, E)).
  
  unique_list(List) when is_list(List) ->
      lists:sort(sets:to_list(sets:from_list(List))).
  
  strip_leading_zeros(<<0, Rest/binary>>) ->
      strip_leading_zeros(Rest);
  strip_leading_zeros(Binary) -> Binary.
  
negative.code: 
  encode_nsec_types([]) -> <<>>;
  encode_nsec_types([_|_]=UnsortedTypes) ->
      [FirstType|_] = Types = lists:usort([int_or_badarg(fun type_to_int/1, Type)
  					 || Type <- UnsortedTypes ]),
      FirstWindowNum = FirstType div 256,
      FirstLastType = FirstWindowNum * 256,
      encode_nsec_types(<<>>, <<>>, FirstWindowNum, FirstLastType, Types).
  