anchor.diff:  %%
   %% API Functions
   %%
  --spec fix2record(binary(), fix_version ()) -> {FixRecord :: tuple(),
  +-spec fix2record(binary(), fix_version ()) -> {FixRecord :: tuple(any()),
                                                  UnkownFields :: list()} 
                                                  | not_valid.
   fix2record(Message, FixVersion) ->
  
positive.code:         false -> not_valid
      end.
  
  -spec record2fix(tuple(), fix_version ()) -> binary() | not_valid.
  record2fix(#custom_message{standardHeader = Header, standardTrailer = Trailer},
             FixVersion) ->
      Utils = get_util_module(FixVersion),
  
negative.code:             completeBinary(Utils, list_to_binary([Bin, Bin2]))
      end.
  
  -spec format(tuple(any()), 
                     fix_version ()) -> string() | not_valid.
  format(#custom_message{standardHeader = Header, standardTrailer = Trailer},
         FixVersion) ->
  