anchor.diff:  
   -spec strip_fields(Fields :: [#'Field'{}]) ->
       [{string(), term()}].
  -    strip_fields(Fields) ->
  +strip_fields(Fields) ->
           strip_fields(Fields, []).
   
   -spec strip_fields(Fields :: [#'Field'{}],
   		   Acc :: [{string(), term()}]) ->
       [{string(), term()}].
  -strip_fields([], Acc) ->
  -    lists:reverse(Acc);
   strip_fields([#'Field'{name = N, value = {boolean, B}} | Rest], Acc) ->
       Bool =
   	case B of
  
positive.code: 	    {binary, list_to_binary(V)}
      end;
  make_value(undefined) ->
      {null, 'NULL'};
  make_value(A) when is_atom(A) ->
      {string, atom_to_list(A)};
  make_value(T) when is_tuple(T) ->
  
negative.code: strip_fields([#'Field'{name = N, value = {null, _}} | Rest], Acc) ->
      strip_fields(Rest, [{N, undefined} | Acc]);
  strip_fields([#'Field'{name = N, value = {_, V}} | Rest], Acc) ->
      strip_fields(Rest, [{N, V} | Acc]);
  strip_fields([], Acc) ->
      lists:reverse(Acc).
  
  -spec validate_attributes(Attr :: [string()], Acc :: [atom()]) ->
      [atom()].
  