anchor.diff:  
   -spec encode_key(?RT:key()) -> integer().
   encode_key(Key) ->
  -    binary:decode_unsigned(term_to_binary(Key)).
  -
  --spec decode_key(integer()) -> ?RT:key().
  -decode_key(IntKey) ->
  -    binary_to_term(binary:encode_unsigned(IntKey)).
  +    term_to_binary(Key).
  +
  +-spec decode_key(binary()) -> ?RT:key().
  +decode_key(BinKey) ->
  +    binary_to_term(BinKey).
  
positive.code: -spec is_pure(cell()) -> boolean().
  is_pure({Count, Key, KeyCheck, Val, ValCheck}) ->
      (Count =:= 1 orelse Count =:= -1) andalso
          ?Check_sum_fun(Key) =:= KeyCheck andalso
          ?Check_sum_fun(Val) =:= ValCheck.
  
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  
negative.code: %% helpers
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  %% @doc Hash function for checksum building.
  -spec checksum_fun(binary() | integer()) -> integer().
  checksum_fun(X) when is_integer(X) -> erlang:crc32(integer_to_list(X));
  checksum_fun(X) -> erlang:crc32(X).
  
  % @doc Increases Val until Val rem Div == 0.
  -spec resize(pos_integer(), pos_integer()) -> pos_integer().
  resize(Val, Div) when Val rem Div == 0 -> 
  