anchor.diff:  -export([read/1]).
   -export([write/2]).
   
  +-export([lease_renew/1]).
  +-export([lease_handover/2]).
  +
   %% filters and checks for rbr_cseq operations
   %% consistency
  --export([is_valid_state_change/2]).
  +-export([is_valid_state_change/3]).
  +-export([is_valid_renewal/3]).
  +-export([is_valid_handover/3]).
   
   -type lease_id() :: ?RT:key().
  --type lease_aux() :: any().
  +-type lease_aux() ::
  +        any().
  +        %% | {aux, empty}
  +        %% %% split
  +        %% | {aux, jhsgjghs} %% 1. L1: 
  +        %%    | 
  +        %%    %% merge
  +%%.
   
   -record(lease, {
             id      = ?required(lease, id     ) :: lease_id(),
  
positive.code:                        case Value of
                             no_value_yet -> {fail, not_found};
                             _ -> {ok, Value}
                             end
                        )
      end.
  
  -spec write(lease_id(), lease_entry()) -> api_tx:write_result().
  write(Key, Value) ->
      %% decide which lease db is responsible, ie. if the key is from
      %% the first quarter of the ring, use lease_db1, if from 2nd
      %% quarter -> use lease_db2, ...
  
negative.code:                                                 % @copyright 2012 Zuse Institute Berlin,
  
                                                  %   Licensed under the Apache License, Version 2.0 (the "License");
                                                  %   you may not use this file except in compliance with the License.
                                                  %   You may obtain a copy of the License at
                                                  %
                                                  %       http://www.apache.org/licenses/LICENSE-2.0
                                                  %
                                                  %   Unless required by applicable law or agreed to in writing, software
                                                  %   distributed under the License is distributed on an "AS IS" BASIS,
                                                  %   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                                  %   See the License for the specific language governing permissions and
                                                  %   limitations under the License.
  
  %% @author Florian Schintke <schintke@zib.de>
  %% @doc lease store based on rbrcseq.
  